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ICD 08559

MARCH 1987 $1.95 CANADA $2.50

THE MAGAZINE FOR ELECTRONICS & COMPUTER ENTHUSIASTS

A DISTRIBUTION AMP PROJECT FOR CLEAN AUDIO & VIDEO 40 USING AN OSCILLOSCOPE TO MAKE DIGITAL LOGIC MEASUREMENTS

nw TO ADD A HARD-DISK Keychain Electronic Project ; p. 68)

C'? TO O !R CARD " ONAL COMPUTER

he EPROM Programw 4K and 128K EPRC te Telephone Bell itlStand-Alone Annurt ia

(Ia. 48i Adding A Hard -Disk Drive to a Personal Computer(p.26) Solid -State Phone Bell Replacement /Annunciator

Bulk Rate Also: Forrest Mims' Keychain Electronic Projects Using SMTs Eric Grevstad's Permit No. 79 First Impressions of the Tandy 3000HL and Words & Figures Don Lancaster U.S. Postage Paid on Genlocking Videc Images, WF Converters, & an Easy Printed -Circuit Process, Gordonsville. VA 22942 etc. Desktop Publishing Power with MacPublisher Electronic & Computer News ... and more.

www.americanradiohistory.com New GPS Series: Tek sets the pace with SmartCursorsM and push -button ease.

Work faster, smarter, with two new Features 2246 general purpose scopes from 2245 Bandwidth Tektronix. The four -channel, 100 MHz 100 MHz 100 MHz 2246 and 2245 set the new, fast pace for No. of Channels 4 4 measurements at the bench or in the Scale Factor Readout Yes Yes field. They're easy to use and afford, by SmartCursors'" design. Yes No On top: the 2246 with exclusive Volts Cursors Yes No integrated push-button measure- Time Cursors Yes No ments. Measurements are accessed Voltmeter Yes No through easy, pop -up menus and imple- Vertical Sensitivity mented at the touch of a button. Mea- 2 mV/div 2 mV/div sure peak volts, peak -to-peak, ± peak, Max. Sweep Speed 2 ns/div 2 ns/div dc volts and gated volts with new hands - Vert/Hor Accuracy 2% 2% off convenience and on- screen readout Trigger Modes Auto Level, Auto, Norm, TV of values. Field, TV Line, Single Sweep SmartCursors`" track voltmeter mea- Trigger Level Readout Yes No surements in the 2246 and visually indi- Weight 6.1 kg 6.1 kg cate where ground and trigger levels are Warranty 3 -year on parts and labor including CRT located. Or use cursors in the manual Price mode for immediate, effortless measure- $2400 $1875 ment of waveform parameters. Both scopes build on performance sensitivity to 0.25 div at 50 MHz, to 0.5 responsive controls and simple front- you haven't seen at the bandwidth or div at 150 MHz. panel design, in extensive on- screen prices. Lab grade features include Accuracy is excellent: 2% at vertical, scale factor readouts, and in sweep speeds to 2 ns/div. Vertical sen- 2% at horizontal. And four-channel simplified trigger operation that includes 2 mV sitivity of /div at full bandwidth for capability includes two channels Tek's Auto Level mode for automatic trig - low -level signal capture. Plus trigger optimized for logic signals. gering on any signal. Start to finish, the Best of all, high performance GPS Series saves steps and simplifies comes with unmatched tasks. convenience. You can Get out in front! Call toll -free today see it and feel it to order, to get more details or a vid- -in the eotape demonstration. 1- 800 -433 -2323 In Oregon, call collect 1- 627--> -9000 ;.::

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www.americanradiohistory.com Which Way To YOUR Future?

Are you at a crossroads in your career? Have you really thought about it? Are you planning for your future, or perhaps refusing to face the subject? Which way will you go - down the same old road? Or are you ready for something else? In electronics you can't stand still. If you are not moving ahead, then you're falling behind. At the crossroads of your career, various choices are available -- and, yes, decisions have to be made. Which road will you take - one that doesn't go where you want to be, or one that leads to hard work but also to the Put Professional better life? Ah, decisions, decisions! KNOWLEDGE Career decisions are so important that you need all the input you can get before locking-in on one of them. Grantham Col- and a lege of Engineering offers you one source of input which may COLLEGE DEGREE that decision. It's our free catalog. help you in making in your Ask for our free catalog and you may be surprised to learn how Electronics Career it is easily possible to earn a B.S. degree in electronics without attending traditional classes. Since you are already in electronics through (you are, aren't you ?), you can complete your B.S. degree work HOME STUDY with Grantham while studying at home or at any convenient place. Grantham offers this program, complete but with - But don't expect to earn that degree without hard out laboratory, to electronics technicians whose work. Any degree that's worth your effort can't be objectives are to upgrade their level of technical had without giving effort to the task. And of course employment. it is what you learn in the process, as much as the degree itself, that makes you stand out above the Recognition and Quality Assurance places you in an enviable position, crowd that Grantham College of Engineering is accredited by -wise and financially. prestige the Accrediting Commission of the National Home Study Council, as a degree -granting institution. Grantham College of Engineering 10570 Humbolt Street All lessons and other study materials, as well as communications between the college and students, are in the Los Alamitos, California, 90720 English language. However, we have students in many foreign countries; about 80% of our students live in the United States of America.

r -1 for Grantham College of Engineering M-3-87 FREE 10570 Humbolt Street, Los Alamitos, CA 90720 Booklet Please mail me your free catalog which explains your CLIP This free booklet B.S. Degree independent -study program. explains the COUPON Grantham B.S. and mail in Name Age Degree Program, envelope or offered by inde- paste on Address pendent study to postal those who work Zip card. City State in electronics.

www.americanradiohistory.com EDITORIAL STAFF RN Art Salsberg Editor -in -Chief EL ICS Alexander W. Burawa THE MAGAZINE FOR ELECTRONICS & COMPUTER ENTHUSIASTS Managing Editor Dorothy Kehrwieder MARCH 1987 VOLUME 4, NUMBER 3 Production Manager Elizabeth Ryan Art Director FEATURES Barbara Scully Artist 16 Logic Signal Measurements Pat Le Blanc Using an oscilloscope to make basic measurements in Florence Martin digital logic circuits. By Robert Ramirez Phototypographers Hal Keith 26 Adding a Hard -Disk Drive Illustrator Installing standard hard drives and hard -disk cards: Bruce Morgan Seagate's ST225 internal hard disk. By TJByers Photographer Western Digital's "FileCard." By Joe Desposito Maynard Electronics' "OnBoard." By Art Salsberg Joseph Desposito, Leonard Feldman, 26 Eric Grevstad, Glenn Hauser, Don Lancaster, Forrest Mims III, 34 An Audio /Video Distribution Amplifier Stan Prentiss Eliminates signal -loss problems when integrating a Contributing Editors variety of audio and video components into a home - entertainment system. By Jack Cunkelman BUSINESS STAFF Richard A. Ross 44 Stand -Alone EPROM Programmer Publisher (Conclusion) Art Salsberg Plug -in module allows basic Programmer to handle Associate Publisher 64K and 128K EPROMs. By Walter W. Schopp Dorothy Kehrwieder General Manager 48 The Ringer Frank V. Fuzia 34 Solid -state telephone bell replacement and stand- Controller alone incoming-call annunciator. By C.R. Ball Arlene Caggiano Accounting Cheryl Chomicki COLUMNS Subscriber Services 58 Hardware Hacker o SALES OFFICES O Author answers readers' questions. Modern Electronics By Don Lancaster o 76 North Broadway Hicksville, NY 11801 64 Software Focus (516) 681-2922 MacPublisher II for Plenty of Desktop Publishing Eastern Advertising Representative Power. By Mike Nikolich Herb Pressman 44 76 North Broadway 68 Electronics Notebook Hicksville, NY 11801 Keychain Electronic Projects. By Forrest M. Mims III (516) 681-2922 LE Midwest & West Advertising Representative /y Z 78 PC Papers Market /Media Associates 339 i Two Hybrids: Tandy 3000HL, Words & Figures. 1150 Wilmette Ave. By Eric Grevstad Wilmette, IL 60091 (312) 251 -2541 L Ted Rickard 1 /4 1 DEPARTMENTS Kevin Sullivan 339 Offices: 76 North Broadway, Hicksville, NY 11801. Tele- phone: (516) 681 -2922. Modern Electronics (ISSN 0748- 4 Editorial 9889) is published monthly by Modern Electronics, Inc. Consumer Rights & Wrongs. By Art Salsberg Application to mail at second class rates pending at Hicksville, NY and other points. Subscription prices (payable in US Dollars only): Domestic -one year + 1/4 14 5 Letters $17.97, two years 533.00, three years $48.00; Canada/ 339 Mexico -one year $20.00, two years $37.00, three years i á - i $54.00; Foreign -one year $22.00, two years $41.00, three years $60.00. Foreign Air Mail -one year $75.00, 6 Modern Electronics News two years $147.00, three years $219.00.

L Entire contents copyright 1987 by Modern Electronics, 11 12 New Products Inc. Modern Electronics or Modern Electronics, Inc. as- 1 /9 13 sumes no responsibility for unsolicited manuscripts. Al- low six weeks 319 for delivery of first issue and for change of i 10 76 Books & Literature address. Printed in the United States of America. Postmaster: Please send change of address notice to Modern Electronics, Inc., 76 North Broadway, Hicks- 68 92 Advertisers Index ville, NY 11801.

2 / MODERN ELECTRONICS Say You Saw It In Modern Electronics

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www.americanradiohistory.com MAC INKER TM 11111111/EDITORIAL II.

MAC INKERr , Automatic Ribbon Re- inker. Re -ink any fabric Consumer Rights & Wrongs cartridge or spool for less than 5 cents. Over 70,000 in the field and we support ..; ALL printers. We have a lot of consumer rights, some widely circulated newsletter gives in- Universal of which have constitutional support. sights to how to give a VC II a "fix." It Cartridge or But that doesn't mean you can do every- talks about coded chip -cloning methods, Universal Spool thing you wish to, even when it might with the ins and outs of modifications, MAC INKER seem that it's legal. For example, it's il- costs for getting a serial- numbered ROM $68.50. We have cartridges legal to yell "Fire!" in a crowded audi- and replicating it, etc. Bad business! re- inkable in 10 colors. Ask for your torium when there is no fire, so don't There are other consumer-rights acti- printer type or for complete listing. look to First Amendment Rights here vities churning that relates to electronics. Bottle ink $3.00/each. shipping $3.00. (and rightly so!) Outstanding among them concerns the In the electronics and computer areas, new generation of digital audio tape re- PROTEUS", the 'Siamese' Buffer. there are a host of "You shall pots" that corders (DATs). It is a Data Switch with buffer on consumers should (but don't always) Audio both ports. recording companies are seek- Switch manually or via obey. Some of these laws software. Saves time, space and change, of ing agreement from equipment manu- money. Or ask course, while others come to the fore- facturers to incorporate a VLSI chip in about our MAC front by being newly introduced. their DAT equipment that would prevent MASTER line On the former, the Communications consumers from recording the copy- of r® Universal ,, eR.. Privacy is Buffers and a Act now public law 99 -508, righted music it contains (and, conse- Printer Controllers (serial or parallel which is effective January 19, 1987. It quently, raise the price the consumer has up to 1 MEG). has enough ambiguities to drive a Mack to pay for the equipment). Happily, the PROTEUS 64 K- 199.00 truck through it, though. It needs a good Electronic Industries Association of Ja- 256 K- 299.00 Shipping $4.00. definition /interpretation of the word, pan, representing hardware makers, re- Of course we have Data Switches, "surreptitious," for example. The way jected this anti -copying circuitry that serial /parallel, 2 way, 4 way, crossed it's worded, any secret listening might be etc., at most competitive prices (all the music industry's representatives lines switched). construed to be a violation, even if it isn't are pushing. specifically prohibited. Would listening EIAJ members said they will not ac- CABLES priced $10 -25. We carry to someone else's marine radiotelephone cept the International Federation of cables for all common computers conversations be illegal under this new Phonogram and Videogram Producers' and peripherals. Rapid turn -around law? I'd say no, even though it is surrep- (IFPI) posture of placing consumers and on custom orders. titious listening. But the law doesn't spell commercial pirates in the same position. it out. Nor does the EIJA agree that home tap- MERCURY MODEM. Really 100% Concerning newly introduced technol- ing suppresses sales of records and tapes, Hayes* Compatible. 300/1200 baud, speaker, full status light display ogy, the people at General Instrument as charged by the IFPI. and 2 years warranty. Includes Corp., which recently purchased M /A- The DAT equipment manufacturers QUICK LINK, Com's Video Cipher Division, appear to have already established a special play- easiest and be worried about pirate satellite TV de- back mode and does not have any digital- most reliable scramblers that are claimed to break se- Comms Soft- to- digital recording capability. Further- ware (available curity of its VC II descrambler box. GI more, DAT's digitization sampling fre- for IBM PC or claims that their investigations show that quency differs from that of CD record- Macintosh) $149.00 Shipping $4.00. many decoders with "fixes" are frauds, ings (48 kHz vs. 44.1 kHz). *Hayes is a trademark of Hayes Microproducts. while other modifications have been anti- Along the lines of what the music in- cipated and can be controlled through dustry is trying to do to squeeze out MAC THE RIPPER. Our newest, original multiple levels security measures money on the large royalties they and welcome printer companion. Pulls off of that top of paper perforations and tears the sheets make the pirate descramblers useless. already receive from records and prere- -apart. Takes little space and will pay for The company notes that the Cable corded tapes, the motion -picture industry itself almost immediately in saved time and tedium. Ask for brochure. Introductory Communications Policy Act of 1984 is also striving to get anti -copy ICs into Price $299.00. Shipping $10.00. makes violators who make or sell prod- VCR equipment, which the U.S. Congress Order Tbll Free. ucts designed to receive encrypted signals will soon be addressing as a result of an Call or write for free brochure. without authorization subject to a fine of appeal from motion -picture companies. up to two in while pi- 1- 800 - 547 -3303 $50,000 and years jail, Everyone agrees that commercial In Oregon 503 -626 -2291 (24 hour line) recipients of these signals without autho- rates are blatant thieves and that steps We are and always will be your rization can be fined up to $1,000 and should be taken to prevent them from jailed for up to six months. pursuing their illegal activities. But C -; mputer Nonetheless, "stealing" signals from this should not come at the expense of HBO, Showtime, etc., must be concern- the consumer. Friends® ing GI in light of its press -release warn- 14250 N.W. Science Park Drive ing. Interestingly, an underground, (Continued on page 80) Portland, Oregon 97229 Telex 4949559 Dealer inquiries welcome.

CIRCLE 21 ON FREE INFORMATION CARD 4 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics www.americanradiohistory.com IIiI/LETTERS Illl11

Reader Feedback ing to give it a complete discharge test, IBM PC, which has only 64K-maxi- One of the greatest applications of a which is not normally desirable). mum motherboard RAM, has its 8284 dual -trace scope was not even mentioned Your team of Forrest M. Mims and clock IC soldered in, so it's necessary to in "Understanding and Using Dual - Don Lancaster make Modern Electronics desolder it and mount a socket in its place Trace Oscilloscopes" (October 1986) - a requirement for the modern electronics in order to install the PCA. -Ed. the viewing of signals on balanced lines person! Franklin Swan (telephone, audio, etc.) using the invert I always purchased "hard to find" Oak Forest, IL and add mode. Also, the need for an iso- parts first so I wouldn't be stuck with a lation or x 10 probe came about to pre- Accelerator Update lot of other parts when the critical ones vent loading caused by the scope's input The $30 PC Speed -up Board article I can't be found. My mistake was believing resistance and capacitance. The isolation wrote in ME's February 1987 issue was the author of the "Ocean Box" in your probe should be used at all times except based on installing the device in Zenith Feb. 1986 issue when he said the IC (Na- when the scope (or its feed cable) is of de- PC compatibles. I discovered too late tional Semiconductor's MM5837) that is sired ideal terminating impedance, ter- that a true -blue IBM PC's 8284 chip, the heart of the device is readily avail- minated to eliminate circuit impedance - mounted on its motherboard, doesn't able. Also two 2.2- megohm potentiome- changing effects. leave enough room to plug in the Acceler- ters are needed. In the "Programmable Ni -Cd Recy- ator. You need a right -angle 18 -pin sock- I do not live in a thinly populated area cler" (same issue), by the time the battery et or another board. We'll send another and have been to several major electron- is discharged to where an assumed 1 volt board at no charge to those with an IBM ics supply houses that are fairly close. per cell is reached, I'll bet 99% batteries machne who ordered and received it. Without exception, they all claimed total in the field will have one or more cells at 0 Anyone else ordering the PCA board ignorance of the existence of such a chip. volt or are already in reverse -charge. A should request it as PCA -IBM. Sorry. One asked if I had transposed the num-

1 -volt per cell discharge is too low. Ideal- Bill Owen NRG Electronics ly, the weakest cell should not go below (Continued on page 80) 1.0 volt (unless you are deliberately try- Also, readers should note that an original

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www.americanradiohistory.com Ill/il/MODERN ELECTRONICS NEWS/I/il/I

OPEN MAC. Open- architecture Apple Macintosh computer versions are soon to debut. Took them three years to recognize the positive aspects of this, which would open the gates for third -party developers to create and produce products to give users greater operating and expansion flexibility. Room for 8088, 8086 and 80286 coprocessor boards _s= report- edly in the works for the upcoming Macs so that IBM compatibility would also be an option.

WHERE DO BATTERIES GO? It seems as if all those small batteries are de- voured as if they were fast -food burgers. Where do they go? According to Eastman Kodak's Ultra Technologies subsidiary, just about everywhere there's a need for reliable portable devices: calculators, audio tape equipment, toys, smoke alarms, clocks and watches, briefcase computers, pocket pagers, 35 -mm cameras, power hand tools, etc. As an example of the wild number of batteries used, consider that 1985 sales of battery -powered watches alone amounted to 123- million units, each of which comes with a battery that has to be replaced yearly. Today, the average household buys about 27 batteries each year for a variety of portable devices.

CUSTOMER -SERVICE ELECTRONIC BULLETIN BOARD. Motorola's Microcomputer Operation developed an electronic bulletin board that's available free to the public 24 hours a day, seven days a week. It features the latest MCU literature, new product information, technical updates, custom ROM information, MCU selector guides, a Motorola sales and distributor directory, etc. You can catch it on a modem by dialing 512 -440 -2725.

EUROPE EMBRACES "SMART" CARDS. Whereas the typical magnetic -strip credit or bank card holds only a few hundred data bits, France's same -size CP8 card stores 8 kilobytes. This capacity allows French university students to keep their academic records on "smart" cards that they carry around with them, providing greater confidentiality than keeping them in central files. Some 16- million such cards will be distributed soon to people in France for electronic shopping, identification, and personal database purposes. About 30- million such cards are already employed for credit phone calls. Other countries, including Norway and Luxembourg, have taken to the new technology. The U.S.'s MasterCard is experimenting with the system, too, and it's expected that a 16K version will be offered in about a year.

KING KONG vs. DONKEY KONG. Universal City Studios must be whipping its management and lawyers as a result of the company's lawsuit filed against Japanese video game maker, Nintendo. The suit claimed that Nintendo's Donkey Kong was infringing on Universal's King Kong trademark. In a countersuit recently upheld by the United States Supreme Court, Nintendo of America Inc. was awarded $1.6- million lawyer's fees and damages from Universal for interfering with Nintendo's sales of the hugely successful Donkey Kong game, said to be the largest sanction awarded in history. The Nintendo Entertainment SystemTM holds a 95% share of the home video game market, producing about 400,000 units a mo}Mh to keep up with Japanese demands. The company's Super Mario Bros. video game cartridge is so popular, that more than 600,000 book copies on tips to play the game have been sold in Japan. Now marketing its products in the U.S., it has awakened new interest in video games here.

6 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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Shirt -Pocket DMM Beckman's new Model DM78 digital multimeter is small enough to fit into a shirt pocket, yet it offers auto - ranging measurement of ac and dc voltage and resistance. The latest DMM to be added to the company's Circuitmate instrument line, the Model DM78 measures only 4.25 " x 2.13 " x 0.4 " and weighs a mere 3.5 ozs. It comes in a billfold -like carrying case that has room inside for storage of the testleads. performed with just a few key- Any single -value functions can be strokes. Complex numbers, ma- graphically depicted and statistical trices, vectors, lists, algebraic ex- data can be plotted. Once an expres- pressions and other types of data can sion is plotted in the display, the user be viewed, edited and used in calcu- can locate an approximate root, lations as easily as ordinary numbers. press a key to record the coordinates, An enhanced operating system al- and use the equation solver to calcu- lows direct entry of algebraic expres- late the root with 12 -digit accuracy. sions to be mixed with RPN (reverse The calculator contains a system for Polish notation) logic operations. converting values between unit sys- Equations can be entered and stored tems. The values of 120 units are in the user's own terms with the cal- built in. culation- solver capability. The cal- Separate alphabetic and numeric culator then solves an equation for keypads are provided. When open, any unknown variable anywhere in the calculator measures 7.5 "W x the equation. On- screen menus and 6.25 "H x 0.5 "D and weighs All measurements appear in a 3' - just 8 soft keys give keystroke digit liquid- crystal display window, access to ozs. $235; $135 for optional compact hundreds of functions without the along with function selected. Dc and printer that communicates with the need for programming. -28C ac voltage ranges are to 2, 20, 200 HP by infrared beam. and 450 volts full -scale, while resis- CIRCLE 2 ON FREE INFORMATION CARD tance ranges are 2k, 20k, 200k and 2000k full- scale. Rated accuracy is Industrial /Scientific 0.7 percent. Bandwidth is 40 to 500 Computer I/O Board Hz, and overload protection is to 650 volts dc or peak ac. $29.95. Step Control Ltd. (Santa Barbara, CA) announced availability of its CIRCLE 1 ON FREE INFORMATION CARD PC -XIO board for industrial and sci- Symbolic -Math Calculator entific applications. The board comes with documentation and soft- Believed to be the first calculator ware that allows users to set up and capable of doing symbolic mathe- use an IBM PC or compatible com- matics, Hewlett -Packard's HP -28C puter to control /communicate with up to eight latchable interrupts to goes beyond numeric calculations to electrical devices and electronic in- provide direct local control of test use symbols or variables so that alge- struments. It can interface up to 72 equipment, assembly or inspection bra and calculus operations can be discrete inputs or outputs and offers devices, robotics, process controls,

8 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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during recording, a line -type comb irons, this 25 -watt iron uses slide -on set plastic handle that is claimed not filter enhances resolution and automa- iron -plated tips that cannot freeze to melt if touched by another hot sol- tic gain control assures tight focus. or stick. dering iron. It comes with a 6 -ft. Audio is processed with a dynamic Available with '/,Z ", % " and %6 " cord with three -prong, positively range of greater than 80 dB. Fre- diameter tips, the X -25 has a thermo- grounded plug. $19.95. quency response is 20 to 20,000 Hz, CIRCLE 9 ON FREE INFORMATION CARD and wow and flutter are specified at less than 0.005%. Recordings of up to 8 hours duration are possible with the VCR, which includes SP, LP and EP speeds. Also included are, 14 -day/ 4 -event timer as well as a quick timer that can be set for one -button recording in 30- minute intervals. Built in are an MTS (stereo) decoder and a 119 -channel cable -ready tuner. The VCR is "SR" compatible, making it compatible with all Pioneer remote systems. A 35- function wireless remote controller, included with the VCR, has an LCD screen that displays the selected channel, day of week and program start and stop times in succession. The VCR mea- to do. The loader program provided sures18 / "W x 13 % "D x 3% "Hand Nonvolatile Memory For can set the user's program (BASIC weighs 17 lbs. 10 ozs. $999.95. Commodore -64 Computers or machine language) to autoload CIRCLE 7 ON FREE INFORMATION CARD A new nonvolatile memory cartridge and run on power -up. Or it can be High- Efficiency from Scinort Micro (Austin, TX) for made available by making a SYS SolderingIron the Commodore 64 computer elimin- jump to the cartridge. ates the tedium of manually loading Batteries, included with the unit, A general -purpose soldering iron frequently used utility programs, preserve stored data for more than a that has the heating element directly function key settings, screen config- year. A write -protect switch guards under its tip for high thermal effi- urations, etc. on power -up. Unlike against accidental write access to the ciency is available from M.M. New- EPROM cartridges, changing the memory. Spare labels are provided man (Marblehead, MA). The Antex contents of the new nonvolatile for noting contents. $24.95 plus Model X -25 soldering iron is said to memory cartridge is quick and easy $2.50 P &H. heat up to 750° F in just 45 seconds. CIRCLE 10 ON FREE INFORMATION CARD Equivalent to conventional 40 -watt

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CIRCLE 14 ON FREE INFORMATION CARD clty State Heathkit®m I (Continued on page 57) Heath Zip Company IA subsidiary of Zenith Electronics Corporation CL -787R1 - L J CIRCLE. NO. 119 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 15

www.americanradiohistory.com Test Instruments Logic Signal Measurements

How to use an oscilloscope to make basic measurements in digital logic circuits

By Robert Ramirez*

If you think digital logic is based on 1 s and Os, you're partially correct. When digital circuits are working logically-as they're supposed to -it's okay to think strictly in terms of is and Os. But when things go wrong (counters don't count, printers don't print, modems don't communicate), you may have to start thinking analog to find the problem and fix it. Always keep in mind that digital logic is really based on analog signals. Ideally, these signals represent is and Os (fixed high and low states), but in reality are still analog signals. As such, they are subject to all the whims of the analog world, such as Fig. 1. Modern oscilloscopes provide more bandwidth at lower prices and with attenuation, distortion, noise, prop- more measurement convenience features, such as direct- readout measurement agation delay, and so forth. What cursors and even pushbutton measurement selections. looks like a 1 may not really be a

good, solid 1 because of amplitude variations meet or offset that don't talked about scope specification. In in the major portion of the rated threshold requirements. A 1 could fact, manufacturers often include it bandwidth. even be two 1 s because of noise -mar- in their scope names. The Tektronix Notice the reference to "sinusoid" gin violations. Or it could be a 1 at 2246 100 -MHz Oscilloscope shown in talking about bandwidth. By defi- the wrong time, or only sometimes, in Fig. 1 is one such example. The nition, a digital signal is not a sinus- because of timing -margin violations. bandwidth specification tells you the oid, though it is made up of many si- Troubleshooting these "analog - frequency range of sinusoids that the nusoids. All of these sinusoids, ex- based" digital problems is best done scope will display without amplitude cept for the fundamental frequency, with an oscilloscope. Though any os- attenuation. Almost without excep- are of higher- frequency harmonics. cilloscope will do for simple prob- tion, dc and very low frequencies are For example, Fig. 2(a) shows a 5- lems, to what is find out really going implied in the specification. The MHz clock such as might be used in a on in marginal logic situations, you scope's amplitude measurement ac- personal computer. It has a dc com- need a good scope and some addi- curacy (such as, vertical accuracy = ponent and a 5 -MHz fundamental measurement tional tricks. 2 %) is guaranteed up to the specified frequency. These two frequency bandwidth, which is commonly fixed components are indicated by vertical Good Scope Defined at the 3 -dB down point, or the point amplitude lines in the clock spectrum Bandwidth is the most commonly where the amplitude of the displayed of Fig. 2(b). Notice that there are *Tektronix, Inc. signal drops to half what it was with- other components present at odd

16 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com 4WELESTRERNopics March 1987

to the input connector. A high -band- v width scope is of questionable value - 5 MHz Clock if its bandwidth cannot be carried to the probe tip, down to what you are o Time actually measuring. To be able to do (a) this requires probes that are matched to the scope. It is a common measurement error to ignore this impor- Scope Amplitude link. Response tant It is also a common measurement 0 dB error to fail to compensate the -3 probes before making measure- - 10 dB- ments. Compensation is usually done with a screwdriver or twist ad- - 20 dB- justment on the probe. It must also 30 dB I I Frequency usually be done at scope settings 15 ' 25 35 ' 45 ' 55 ' 65 75 ' 85 ' 95 105 Frequency in MHz specified by the manufacturer. The tt 100 MHz effects of an uncompensated probe D Fundamental 5 -MHz Clock Spectrum Bandwidth are shown in Fig. 3. Using an uncom- (b) pensated probe can result in amplitude or risetime measurement errors. Fig. 2. Digital signals (a) are composed of harmonically related sinusoids (b). Accurate oscilloscope displays require adequate bandwidth to include high er- Is a I a 0 or Two or None? order harmonics. Selecting a good scope is the first step in making measurements. Putting it multiples of the fundamental (15 to proper use is the next step. Time Measurement Accuracy MHz, 25 MHz, 35 MHz, etc.) and For example, in measuring digital that their amplitudes diminish with Risetime Ratio Approximate TO Error signal amplitudes, it is important to (Pulse:Scope) in Time Measurement each successively higher multiple. recognize the type of signal being Higher -order multiples of the 7:1 1 dealt with and to use proper scope in- clock frequency are the harmonics 5:1 2 put coupling. Figure 4 shows three 5.5 that give the clock pulses their cor- 3:1 typical signal types -bidirectional 2:1 12 ners and fast transitions. If you use a (a), uni- directional (b), and uni -di- 1:1 40 scope that has too low a bandwidth, rectional with offset (c). Without a zero reference, uni- directional sig- you basically filter out (attenuate) Scope Tr = 0.35 /scope bandwidth these higher harmonics and their nals are indistinguishable from bi -di- contribution to pulse shape. A high- rectional signals. So it is important er-bandwidth scope, as indicated by to, first of all, establish a 0 -volt base- the response curve in Fig. 2(b), pre- Also, as a general rule for accurate line on the scope display. This is serves more harmonics of the clock time measurements, you should use a done with the scope's triggering set signal, or any other nonsinusoidal scope with a risetime that is at least to "peak -to -peak auto" and the signal for that matter. five times greater than the risetime of probe input coupling switch set to When dealing with digital signals, the pulse you are trying to measure. ground. The resulting 0 -volt display it is often more convenient to think Thus, a 3.5- nanosecond scope pro- is then vertically positioned to a con- in terms of scope risetime, rather vides best accuracy (less than 2% er- venient scale line on the scope screen. than bandwidth and signal harmon- ror) on time measurements up to Then probe input coupling is switched ics. Risetime indicates how fast the about 17 nanoseconds. But this can to the setting (ac or dc) for the signal scope responds to an ideal voltage be pushed, as indicated in the Table, to be displayed. step. As a rule, a scope's approxi- if less accuracy can be tolerated. For most logic signals, dc coupling mate risetime is related to bandwidth For accurate measurements, it is is the best setting. If ac coupling is by Tr = 0.35/BW, where Tr is rise- important that the bandwidth and used, uni- directional signals will time and BW is bandwidth in Hertz. risetime specifications be to the have their dc component blocked Thus, a 100 -MHz scope has a 3.5- probe tip. Because this is not always and will appear as bidirectional sig- nanosecond risetime. done, some scopes are specified only nals. Even worse, any amplitude

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 17

www.americanradiohistory.com Fig. 3. Probe compensation is important in measurement accuracy. Undercompensation (a) results in risetime errors; overcompensation (b) results in amplitude errors; proper compensation (c) results in accurate signal display.

Bi- Directional (a) E iPeAVA V "//,%%í%//'////.%

(a) (b) } ? Uni -Directional 0 0

}? Uni -Directional (c) 0 With Offset 1 Offset

Fig. 4. Three typical types of logic signals. Shaded areas represent bands of indecision, where the signal could be sensed as either a logic 0 or a logic 1.

(b)

Peak-to- +Peak Peak

-Peak 0 Volt I Baseline

1+ Peak Peak -to- 0 Volt Peak Baseline 1 -Peak

Fig. S. Definitions of amplitude measurements relative to (c) a 0 -volt baseline.

18 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com LL4b 'r ir

Fig. 6. A modern oscilloscope provides menu selection of measurements (a) and shows results on- screen (b) with readout and automatic cursor placement (dotted lines). measurements will be ambiguous, the measurements are made by placement of measurement cursors, since the signal is shifted from its accounting divisions from the baseline -the dotted lines in Fig. 6(b). tual dc baseline. Dc coupling, on the and multiplying the count by the The measurement cursors shown other hand, preserves the signal's dc scope's scale factor readout. Modern in Fig. 6(b) can also be manually po- component. oscilloscopes, such as the Tektronix sitioned on- screen to measure the The importance of accurate ampli- 2246 GPS (General Purpose Scope), voltage difference between any two tude measurements is further em- simplify this process considerably. amplitude points. This is useful, for phasized by considering the shaded As shown in Fig. 6, the 2246 GPS example, in checking digital signal "undecided" zones in Fig. 4. For ex- provides pushbutton selection of noise margins. By placing the cursors ample, if the logic signal in Fig. 4(a) measurements from an on- screen at the logic decision levels, you can is being loaded down or attenuated, menu. When a measurement is se- easily observe whether noise, ampli- it may not transition far enough to lected, the 2246 automatically keeps tude drift or signal aberrations are solidly pass the decision zone and be- track of where the zero baseline is crossing the threshold and causing come a solid logic 1 or O. The signal and makes the selected measurement false ones or zeros (Fig. 7). voltmeter. could look like a valid logic signal, with a built -in waveform Is It a I In Time? but its low amplitude could result in The measurement result is displayed ambiguous detection of logic levels. in the on- screen readout and is indi- Measurement cursors offer the same In Fig. 4(b), low amplitudes could re- cated on the waveform by automatic convenience in making time mea- sult in detection as all zeros. In Fig. 4(c), too much offset could result in an all ls detection. When troubleshooting logic circuits, it's not enough to just look at the signal and say, "yes it's there." The amplitudes must be measured to ensure that they solidly pass the 1/0 decision levels. Does the signal have sufficient peak -to -peak swing, or + peak, or - peak swing? Is there offset? Should it be there, and if so, is the offset value correct? The definitions for these measure- Fig. 7. Cursors can be manually placed for amplitude measurements, or (as ments are shown in Fig. 5. Typically, shown) can be used as amplitude markers for observing noise violations.

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 19

www.americanradiohistory.com measure the time difference between leading edges on the resulting dual - channel display of the input and output logic pulses. Other timing measurements you might want to make in troubleshooting a design are pulse width and pulse jitter. Pulse width is critical, since a "1" state must be maintained long enough to be recognized as a 1. This is generally referred to as minimum setup and hold time. When pressing digital designs for maximum speed, it is easy to get pulse width violations. This can happen, for example, because of a small amount of channel skew at the inputs to an AND gate; the input time off- sets can result in an ANDed signal that is too narrow for the next logic stage to recognize. Even if pulse width is kept longer Fig. 8. Cursors can be used in a time measurement mode for checking pulse the absolute minimum, there width, logic line -up (skew) and other timing relationships. than can still be occasional violations from pulse or timing jitter. These are generally referred to as timing mar- surements. This is shown in Fig. 8, play horizontally by a factor of 10, gin violations. Again, measurement where the cursors have been placed effectively zooming in on the center cursors serve as convenient markers for a timing measurement between of the display. In this expanded for detailed observation of timing logic channels. The measurement re- mode, you can get a higher resolu- margins. The cursors can be placed sult (time between cursors) is shown tion measurement of skew and deter- at the timing limits around a transi- in the upper right of the display. mine whether it exceeds the timing tion. This allows you to easily see oc- It is particularly important to note margin specifications of the system casional jitter or timing drift that vi- in Fig. 8 that multiple channels are on which you are working. olates the margin limits. being displayed. Multi -channel dis- Channel skew is usually the result play capability is a necessity for logic of mismatched delays in the logic cir- signals, since many of the critical cuits used in each channel path. This Overshoot Kills CMOS timing relationships are between log- could be a design flaw, which can be Generally, sufficient logic amplitude ic channels. A dual- channel scope is corrected by buffering faster chan- and correct logic channel timing rela- needed at minimum for logic signal nels to delay or "de- skew" them. Or tionships will solve most digital cir- comparisons. However, a four - excessive skew can be the results of a cuit problems. However, with to- channel scope adds convenience by circuit malfunction causing excessive day's more sensitive circuits, too being able to display more signals propagation delay through a gate. much logic swing can be just as bad simultaneously. These propagation delays -delay as not enough. Note also in Fig. 8 how the cursors time between application of an input Overdriving a logic element can verify the signal edge lineup. A signal signal and appearance of an output cause excessive saturation and ex- edge slightly offset from the cursors response -are relatively simple to tend transistor storage time. This re- would indicate channel skew (time measure with a dual- channel scope. sults in pulse stretching, which can offset) between digital signal lines. To measure propagation delay, cause logic or timing errors or force For closer observation of skew, it is put the scope's channel -1 probe on you to run the circuit at a lower than best to position the suspect signal on the gate input and the channel -2 desired clock rate. the scope's center screen division and probe on the gate output. Then, in Even if your nominal signal high is select the x 10 horizontal magnifica- alternate sweep or chopped mode tion function. This expands the dis- and with triggering set for channel 1, (Continued on page 91)

20 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 21

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www.americanradiohistory.com Computers Adding A Hard-Disk Drive An important upgrade operation for the IBM PC and XT and compatibles is examined here, focusing on installing standard hard drives and newer hard-disk cards.

Hand -disk drives are no longer a luxury. For many computer users, they're as necessary as an automatic transmission in an automobile. If you're one of the millions of owners of a floppy - disk -based IBM PC or compatible, you've doubtlessly considered adding one. Today it's easier and less costly to do than ever before. The advantages of having a hard - disk drive are well known: faster operating speed and greater data storage capacity. It's common to enjoy a 10 to 20 times increase in data reading and writing time with a hard disk, as compared to a floppy, for example. Equally important, storage capacity of a typical hard -disk drive bought for upgrading purposes is 20 megabytes, compared to the 360K capacity of a floppy disk. (You can, of course, get a 10 -MB hard disk and spend less money, or a 40 -MB one for giant storage purposes, but the An inside view of an IBM PC that is a candidate for a hard -disk drive. The 20 -MB drive is the most popular.) power supply bulks large behind the full -height floppy -disk drive electronics, As welcome as it is to significantly though it is sadly underpowered. increase data access time from a me- chanical contrivance, storage capacity has been the driving force for add- ory- resident programs -desk acces- later. To check the date, simply enter ing a hard -disk drive today, due to sories, macros, disk managers, DEBUG from your disk -operating the convenience of holding a host or etc. -that can be automatically load- system (DOS) and then type the fol- programs on one disk. This elimin- ed from a hard -disk drive instead lowing: "D F000:FFF5 FFFC" and ates the constant bother of having to of going through all the floppy -disk press ENTER. The screen will display remove and insert floppy disks again motions that would otherwise be the date. If it's earlier than noted, and again. You cannot imagine the required. you'll have to exchange the ROM, delight of pressing a key or two to get If you own an old IBM PC, the which costs about $30. a listing of synonyms in a screen win- PC1 with a 64K system board, its Also, the original IBM PC's pow- dow without changing disks or even BIOS ROM will have to be changed er supply provides only 53.5 watts, exiting the program you're in. New in order for your system to recognize which may or may not be sufficient, vistas of operating convenience are the existence of a hard -disk drive. depending on the new drive you're opened through use of many mem- The ROM's date must be 10 -27 -82 or installing and what you've got in the

26 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com way of total memory and other expansion boards. It's easy to substitute the power supply, which should be 130 watts or even 150 watts. About $75 or so will do it should this be needed. Drive Choices You've got lots of choices to make. Should you get an internal hard -disk drive or an external one? If you plan to have a drive with 10 MB or 20 MB, as most upgraders do, by all means get an internal drive. You don't want to take up any more space than you have to. Should you get a hard -disk drive and separate constroller or an all -in- one hard -disk card? There are a few considerations to weigh here. For ex- in If your BIOS ROM (U33 IC) is dated before 10/27/82, you will have to replace it ample, if you have two full- height order for the hard -disk drive to be booted. floppy -disk drives, you'll want to remove and eliminate use of one of them in order to mount a hard -disk About the ROM using software. Most manufacturers of drive (with separate controller) in its hard -disk drives include a diskette of IBM has not always supported hard - place. If your present installation has hardware- related programs along with disk drives for the PC. The problem height floppy drives, one their products. Among the programs, two half- stems from a missing code in the older you'll find a software patch to DOS atop the other, then you've got the BIOS (Basic Input /Output System) that installs the missing BIOS code into space to install a hard drive (even two chips. ROM chips manufactured before your system. Unfortunately, every time half- heights) and retain use of both the fall of 1982 are in this category. To the system is shut down, the code is lost diskette drives. find the date of your ROM chip, run the and has to be reinstalled on power -up Alternatively, if you have to give following BASIC program: before the hard -disk drive can be used. one of your floppy drives -but up 10 KEY OFF: CLS The second cure involves replacing could go the don't want to -you 20 DEF SEG = HF000 the BIOS chip inside the machine. The do hard -disk card route. You could 30 LOCATE 12,40 procedure is an easy one. Simply locate this in any case, naturally. Keep in 40 FOR X = HFFF5 TO HFFFE your old U33 ROM chip on the mother- mind, though, that a hard -disk card 50 PRINT CHR$(PEEK (X)); board and replace it with an updated is more costly than a basic separate 60 NEXT X ROM chip available from IBM. The drive /controller. We're assuming If you see a date of October 27, 1982 IBM Cat. No. is 1005, and it sells for here that you're not planning to buy or later, your computer can support a about $30. top -of -line drive /controller models, hard disk. Be advised, however, that you can- You which cost much more than the For those with a BIOS date that reads not purchase the chip outright. first remove your old ROM chip under -$400 price mentioned, though before October 27, 1982, your machine must and exchange it at an IBM -authorized they feature greatly increased speed, cannot support a hard disk. Fortunate- two fixes. The first is done dealer for the upgraded version. super sturdiness and all. You'll pay ly. there are at least $100 more for the card and probably a few hundred more for a know that access -time name brand. The card drives will us- might be able to avoid having to buy You should can be an overrated factor, ually (but not always) provide faster a new power supply. speeds since there are other considerations access time, however, and you elimi- If you go the separates route, be how quickly you can read nate installation efforts, since you sure you get a bezel with your kit to that affect and write data. There's an interleave simply plug them into an expansion cover the half- height area that will be factor for the distribution sequence slot. No cables or anything. Also, the exposed when you install a half- height sectors, data transfer time, and cards draw very little power, so you (the likely choice) hard -disk drive. of

ELECTRONICS / 27 Say You Saw It In Modern Electronics March 1987 / MODERN

www.americanradiohistory.com other indexes to weigh. As an exam- tant. File size, file contiguousness, however, are enormous and immedi- ple, a PC XT'a hard -disk drive might and a program's disk intensiveness ately realized. It represents a giant have an average access time of, say, are other factors that must be taken step in operating efficiency, raw 85 milliseconds, while an IBM AT's into consideration. power and convenience. drive might benchmark at 45 ms. Not Deciding to go the hard -disk drive Here are personal experiences of bad, eh? Now let's look at one other upgrade route, which about 15 per- three people who installed hard -disk factor, transfer time. Here, the XT cent of Modern Electronics readers drives in a floppy- disk -based IBM or might be 1,220 ms, while the AT indicate they will do within the year, compatible machine: a separate would be about 610 ms under the according to a study made, does not drive /controller (Seagate's popular same conditions (a large fragmented represent an overwhelming invest- half- height ST225); a 20 -MB hard - file). Clearly, average access time has ment in money, and installation can disk card (Maynard Electronics' to be weighed against other factors. be as easy as snapping in a board or a "OnBoard 20 "); and Western Digi- So it is one of the benchmarks to con- little work physically mounting a tal's 10 -MB "File Card" hard -disk sider and the one likely cited, but drive and then plugging in its con- card and Memory Enhancer. Each is others could be much more impor- troller and cables. The benefits, distinctly different.

1. The Internal Hard -Disk Drive /Controller

If you own an IBM PC or clone, you un- doubtedly realize how dated the machine has become. It's now puny compared to today's powerhouses like the IBM PC/ XT, PC /AT and many compatibles. There are several add -on options that can give performance punch to your present system. Among the most useful is the hard - disk drive. Dollar for dollar, a hard disk is the best performance investment you can make to your system today. A 20- megabyte drive that cost $1,800 only two years ago now sells from some vendors for less than $400.

Installing a Hard -Disk Drive Installing a hard -disk drive into your system is a relatively simple procedure. Most dealers sell hard -disk kits that contain the hard -disk drive, a hard -disk controller card, necessary cables, front panel bezel replacement, and an installation manual. With the kit, installing a hard - Fig. 1. The hard disk spins at the high speed of 3,600 rpm, creating a ground effect that disk drive takes less than 30 minutes. I allows the head to actually float above the platter without touching it. used a Seagate ST225 hard drive in this instance, which is a 20 -MB, half- height unit that's widely sold by mail -order course, is to make sure that the power system's cables. You may need to tilt houses. cord is disconnected. the case slightly to avoid snagging the For convenience, we demonstrate the Remove the rear -panel screws holding front panel. procedure using an IBM PC, but owners the outside case in place and slide the cov- Next, decide where you want to install of PC compatibles should be able to use er forward, taking care that the center your new hard drive. Hard -disk drives the same method. The first step, of screw support doesn't catch on the come in many sizes, including 'A-height,

28 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com %,-height and full- height, and the size of the unit plays an important role in where it can fit in the chassis. The easiest route is to remove the "B" floppy-disk drive and replace it with the hard disk, assuming you've got full- height drives. If you have half- height floppy drives, one atop the other, then you've got a clear area to install the hard drive and you can retain use of both floppy drives. (And you don't have to spend any time removing r,;,,,A, the second one.) rry, The "B" drive is held in place by two fl(n Ii,i?'f . screws located to the right of the unit as ` },...... viewed from the front. Remove these ii.f screws. Then gently slide the unit for- _--__.. ward until you can disconnect the cables connecting the drive to the power supply and controller card. Tuck the controller cable safely out of the way, as it is no longer used. Continue to slide the drive forward until it's clear of the case. You're now ready to install the hard disk, in this case, the Seagate 20 -MB model. Somewhere in the manual is a listing of computer switch settings to make for your new disk drive. The switch may be either a jumper plug or a DIP switch that "tells" the disk drive whether your system contains more than one hard -disk drive or not. Manual in hand, select the proper drive setting. Pig. 2. Before using the hard -disk drive, the Number 1 setup switch must be reconfig- Now slide the drive into the slot pre- ured, as detailed in the above drawing. viously occupied by the "B" floppy drive. Before you secure it with the two screws removed from the floppy -disk drive, connect the power supply cord and controller cables. One controller cable has 34 pins, the other 20 pins, and both have a locating key that prevents you from installing them incorrectly. The opposite ends of these two cables connect to the controller board. While most controller boards come properly configured from the factory, it's possible that a switch setting or two may have to be changed to accommodate your system. If so, make the changes now. While on the subject of setup switches, it's now time to configure the computer's motherboard switches to reflect your system changes. The change is made to Switch Block 1, pins 1, 7 and 8. Pin 1 should be OFF and pins 7 and 8 should be ON, as shown in Fig. 2. to Complete installation by plugging the When installing a half-height hard -disk drive in an IBM PC, it may be advantageous the B -drive controller board into an open expansion mount the hard disk just below a half-height floppy -disk drive, rather than in are used to se- slot in your computer. Be aware that the opening. This frees the right -hand slot for future expansion. Metal straps board is susceptible to damage from cure the two units to the chassis mounting.

29 Say You Saw It In Modern Electronics March 1987 1 MODERN ELECTRONICS /

www.americanradiohistory.com static discharge. Therefore, make sure your body is free of static electricity by touching your hands to the metal chassis before handling this or any other adapter board. It will probably be necessary to route the controller cables so that they are not in the way of the cover. If your hard drive is only half- height, which most are, your kit contains a bezel that fills the empty slot above the hard drive on the front panel. Install it now. Check your work for errors, and then replace the outside cover.

Formatting , '1144;.;???,.., *`e?ri.;_ ;f7" Your is now .,a .ia. hard disk ready for service. . . ,,'. . . .:.-' . . ', '.'; Unlike floppy diskettes, though, your hard disk requires two types of formatting before it can be used: a physical format and a logical format. Both formats are made using your disk -operating system (DOS Version 2.xx or 3.xx). Physical formatting arranges the structure of the information on the disk media. Information is organized into sectors and clusters. A sector is an area on the disk that contains 512 bytes of data. A cluster is a group of sectors that the hard disk, for management purposes, treats as one. Let's say, for example, that you have a file containing 1,000 bytes. Obviously, this file requires two 512 -byte sectors of disk space. But the hard disk doesn't recognize individual sectors per se. Such a chore would take up much too much management space on the disk. What the drive does is group sectors into clusters of 4, 8 or 16, and treats them as one. When writing a file to the disk, you're actually writing to a cluster. An IBM PC with all disk drives removed is shown in upper photo. Lower photo shows a This arrangement would be fine if all half-height hard -disk drive installed below a half-height floppy drive at left, with second files were of a size commensurate with drive slot at right covered by a bezel. Other installation arrangements are possible. the size of a cluster. But they're not. If we were to write our 1,000 -byte file to a disk formatted with four sectors to the cluster, only half of the available sectors your DOS program diskette to erase the turn on your machine and let it boot. At would be used, leaving a full 50 percent previous cluster settings. the DOS prompt, type: "FDISK" and of the cluster empty. And, regrettably, The type of DOS you're using has an press ENTER. You are now given a menu no other file or record can make use of effect on the size of the cluster. DOS Ver- of FDISK options. Choose option [3]: these left -over sectors. They are assigned sion 2.1, for example, formats its disks deleting the DOS partition. Essentially, one file and one file alone, no matter using a 4K (8- sector) cluster and doesn't this command wipes your disk blank, in- what their size. support hard -disk drives larger than 10 cluding the formatted cluster size. A Generally, cluster size is specified by MB in capacity. DOS 3.1, on the other warning screen will appear informing the disk maker at the time of manufac- hand, formats in 2K clusters and sup- you that the information on the hard disk ture. To reset the size of the clusters, you ports disk drives of up to 32 MB. is about to be destroyed, to which you re- must use the FDISK program found on With the DOS diskette in drive "A," spond with a "Y."

30 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com (notice that periods are not ac- You must now create a new DOS parti- ters place the boot commands and a label DOS 3_1 label characters). tion using option [1] of your FDISK on the disk, respectively. You will be ceptable The hard disk is now ready for use. menu. The process is automatic; simply warned of data loss at this time, but not average access time of the Seagate press ENTER in response to all questions. to worry. Proceed by answering "Y" to The I installed is 68.5 ms, using a Core The hard disk is now ready for logical the statement. ST225 test disk. This disk drive's formatting. The logical format prepares Depending on the size of the disk in- International and large storage capacity, as the drive with DOS -specific informa- volved, logical formatting can take up to high speed to floppies, is impressive. tion vital to system operation. At the several minutes to complete, so relax. compared get accustomed to using your DOS prompt, type "FORMAT" C: /S/V" The formatting process is complete when Once you you'll wonder how you ever and then hit ENTER. The FORMAT you are asked to enter a disk label name hard disk, without it. command sections the disk and lists any of up to 11 characters long. I suggest us- got along -TJ Byers bad sectors, while the /S and /V parame- ing the DOS version for the label; i.e.,

2. FileCard

Adding a hard disk to your IBM PC or XT or compatible computer has been made even easier with hard disk /controllers that plug right into an expansion slot. Two representative models are examined here: Western Digital's "FileCard" and Maynard Electronics' "OnBoard." Western Digital, which had previously marketed its wares through OEM channels, has now gone retail with some products, including the 10 -Mbyte hard -disk drive card examined here that can be placed in an IBM PC /XT or compatible expansion slot. Its 3.5" drive, which is approximately 1 " wide, is attached to a Western digital controller card. An optional memory card, which can hold up to 512K of RAM, can be attached to the board. Suggested retail price of the File - Card is $795, and the memory card is $99 with OK of RAM installed. (The memory with the option of daughterboard is being given free by Western Digital's low power, 10-MB FileCard combines mass storage controller many dealers with a FileCard purchase.) RAM memory on a small daughterboard (lower-left) that mounts on hard -disk card without taking up additional slot space. Installation Installation of the card is straightfor- The width of the drive section on File - ward and is as simple as adding any other Attaching the memory board to the Card causes it to use 11h slots. The extra kind of expansion board. The manufac- card is also a simple process. The card half slot that FileCard uses means that turer suggests anchoring the drive on its plugs into a 34- contact /double -row con- you cannot put a full -size expansion far side with screws, which is easiest to do nector on the board and is secured by two board next to a FileCard unless you use on the IBM PC or XT. On other systems, screws at the other end. Then the DIP Slot 1. To do this, you will have to move like the Compaq or AT &T 6300, a special switches on the board and in the system the internal speaker. Otherwise, only a bracket is included to accommodate the must be correctly set according to the half -size expansion board can be in- peculiarities of each computer's chassis. amount of memory employed. This step stalled next to FileCard. If FileCard is not the first hard -disk is also well -detailed in the manual. Since Once you load FileCard into an expan- drive to be installed in the system, certain the component side is installed face- sion slot, your hardware chores are over, jumper wires on the board must be down, adding only a hair -width to the but there still remains a software setup to changed. These changes are thoroughly FileCard, it doesn't infringe on an adja- perform. Normally, a hard disk must un- detailed in the manual. cent slot's turf.

MODERN ELECTRONICS / 31 Say You Saw It In Modern Electronics March 1987 /

www.americanradiohistory.com dergo a low -level or physical formatting, rpm (a floppy drive revolves the disk at with one row unpopulated (256K). Thus, and then a logical formatting with the only 300 rpm). Further, its transfer rate is there are lots of expansion options with- DOS FORMAT command. Western Di- 3.2 Mbits /sec. compared to an industry out giving up another slot. gital, however, makes things as easy as standard of 5 Mbits /sec. Interestingly, Another possible advantage of a plug - pie for the customer, shipping the disk al- we also discovered that we could not in hard disk like FileCard is its portabil- ready physically formatted, and with an sense a difference in speed between it and ity. At a weight of just 2 lbs. 4 ozs., it is install program to do the rest of the setup hard -disk drives with twice the speed in very easy to remove FileCard from one task. So typing "INSTALL" is normally the same machine. Perhaps we would PC and install it in another. However, all that is necessary in most cases to get with heavily fragmented files. But File - one should handle a hard disk gently, the drive up and running. Card was plenty fast in use. since it is a fragile device that could lose Sometimes, however, programs on a Another drawback of the drive is that its information if subjected to too much hard disk can become damaged in ship- you don't get to see the red indicator light of a shock. FileCard's shock resistance ping and the work done at the factory when it goes on, since it is tucked away specification is a nice 70 G when the must be repeated. In our case, the IN- inside the unit. This was a problem for us heads are parked, however (and 5 G STALL program bogged down before it when the INSTALL program crashed, when not parked). completed its task. It was then a matter for we really didn't know if the drive had There are two sets of documentation of trial and error to see how much the IN- stopped or not, and thus waited longer for FileCard: one for the card and mem- STALL program had accomplished and than we should have to abort the program. ory board and one for XTREE. The File - what was left to do. Although the IN- Once up and running, however, we ob- Card documentation is thorough and STALL program simplifies the proce- served that FileCard's automatic head - highlighted with many photos and draw- dure of getting the disk up and running, parking feature does more than activate ings. However, it is probably wise to sup- there is no substitute for knowing the when power is shut down. It also parks plement the documentation with DOS DOS procedures themselves. For exam- the heads when you don't use the compu- documentation for hard disks. Docu- ple, the INSTALL program creates only ter for 5 seconds or so, emitting an easily mentation for XTREE is good, although a DOS partition on the disk. If you want heard whirring sound as it does so. The the program is so simple to operate that more than one partition, you have to use drive itself is very quiet. Sometimes, documentation is probably not needed the DOS FDISK command anyway. hard -disk noise can be bothersome, since for most uses. the disk is constantly spinning. With File - Western Digital's FileCard attempts to Using the Hard Disk Card, this high -pitched noise is satisfac- set a new standard for ease of installation torily muffled. and operation of a hard disk. For this In its quest to make FileCard the easiest Though you lose a slot when installing benefit, the cost of a 10 -Mbyte card is product to install and use, Western Digi- a FileCard (you'd lose half a slot anyway substantially more than for some faster tal also includes an excellent hard -disk for the separate controller if you install a standard 20 -Mbyte internal disks. Is the management program called XTREE conventional hard disk), you do gain an benefit worth the cost? from Executive Systems (Sherman Oaks, extra floppy -disk drive that would have I think it is in many, but not all, instan- This CA). utility program helps you to to be removed when installing a standard ces. It is, I believe, if you must add a se- manage the hard disk by making it easy internal hard disk (unless half- height cond hard disk or if you don't want to to create subdirectories and to view the drives are used). The extra floppy drive is give up one of your two floppy -disk láyout of the disk once multiple directo- always useful in a system. Too, if you drives. Or if you just don't want the ries are in use. XTREE also makes it a have a machine with a 10 -MB hard disk bother of maneuveing an internal drive snap to copy and delete one or more files and you need more storage capacity, it into place and squishing more cables into on the hard disk. This program is a smart represents a way out beyond dumping the an already tight enclosure. Or if your addition to the product. 10 -MB drive to substitute a larger -capa- power supply is the original PC 1's under- One of the reasons to buy a hard disk, city drive or adding a desk -space- taking rated unit. Or if you need more RAM besides capacity, is for speed. Unfortu- external drive. memory. In these cases, however, I'd nately, FileCard falls short in this area. Power drain of FileCard is only 5.3 spring for another $100 (list price) and The disk is rated with an average access watts, which is another plus for PC own- get the 20 -Mbyte FileCard instead of the time of 147 milliseconds. When sub- ers whose power supplies can be strained 10 -Mbyte examined here. It'll be one of jected to our Core International test for by hard disks requiring more power. the best -spent $100 in your life. disk speed, we measured the average ac- Adding the memory plug -in card to File - If the conditions cited are not one of cess time to be 164 ms. Normally, a hard Card, fully populated with 512K of RAM, your driving reasons, I'd recommend a drive on an IBM XT has an average ac- adds only 0.75 watt. standard internal hard -disk drive. They're cess time of 93 ms, using the same source, The memory board can be a Godsend a lot cheaper and not that difficult to in- though its rating is 80 ms or so. to users who have not yet brought their stall. Also, there are some hard -disk We wondered why FileCard's access computers up to full capacity. It accom- cards that are hundreds of dollars cheap- time lagged behind that of most other modates two rows (nine devices each) of er. They won't have Western Digital's hard disks. A little research revealed that RAM. This can be 18 256K chips (512K), magnificent -quality components and its rotational speed is only 2,322 rpm in 18 64K chips (128K), nine 256K and nine workmanship, though. contrast to a hard- disk's standard 3,600 64K chips (360K), or nine 256K chips - Joe Desposito

32 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com 3. OnBoard

Maynard Electronics entered the hard - disk card arena early. Its OnBoard model is available in two storage capacities: 10 Mb and 20 Mb. (Like all counts of memory, there is actually more than stated since numbers are neatly rounded off. A 20 -Mb drive is really a 21 -Mb+ drive, for example, just as a 64K chip actually has more than 65K of memory.) OnBoard typifies what most hard -disk cards look like, a rectangular body with one half containing the drive and the complementing other half the electronics and slot- connector contacts. The $895 20 -Mb drive tested is more costly than some hard -disk cards, but Maynard Electronics' OnBoard 10 and 20 offer 10 and 20 MB of mass storage capacity, not the highest. Unlike many hard -disk respectively. There are now 30-MB hard cards on the market as well. drives and cards, the one we worked with had no bad sectors. (Hard disks often have a few imperfections, you know, so the existing hard -disk drive; just add to recognizes this opportunity and shows it's not unusual to get one with some bad it. Since OnBoard can control the second how to do it in its manual, it also offers a sectors locked out at the factory. Not to drive, with the addition of dual -drive free clip -on adapter to mount the speaker worry if this is the case, since the storage cables available from Maynard that sim- on the hard-drive card should such new memory lost is only a drop in the bucket.) ply plug into a connector on the card, the speaker- mounting space not be avail- The drive worked flawlessly for a half original hard -disk drive's controller can able. Clever! year while on loan, so its design /con- be removed, saving a slot. Internal diagnostics run automatically struction promises good reliability. Another worthy feature of OnBoard is on power -up, says the manual. Since we Using the floppy disk program sup- the ability to set up a screen indicator never suffered with as much as a glitch in plied with the card, formatting the hard (flashing dot) and /or sound indicator all the time we worked with the drive, so disk was almost as easy as installing it. (beeping sound) to let you know when we'll take the maker's word for it. Interestingly, the disk contains a pro- the internal hard disk is operating. The The only criticism we can make relat- gram for early PCs that cannot boot a indicators can be turned on and off. The ing to OnBoard is our initial impression hard -disk drive. Copying the short pro- hard drive, by the way, is unusually quiet of the absence of an automatic head -park gram onto a floppy, the latter can be used in operation. feature when power is turned off. This is as a key disk to boot the hard disk, obvi- As with all hard -disk cards we know a good insurance policy to have, especial- ating an absolute need to change an old of, excepting Plus Development's "Hard - ly if something happens with the compu- ROM. This works with DOS 2.xx only. If card," the Maynard card takes up 11/z exter that prevents booting the support disk you use DOS 3.xx, you'll have to get the pansion slots. That is, the drive portion's to park the heads for shipping or other- new ROM. The support disk also con- width of the card encroaches into the wise rough treatment. Checking this out tains programs for "parking" the hard space of a second slot, while the electron- with the company, I was assured that the disk for use when moving it to another lo- ics section does not. Thus, only a half - drive did indeed have an automatic head - cation, a utility to indicate the hard - card can be used in front of OnBoard, as park feature upon shutdown that posi- disk drive's BIOS number, hard drive with most other hard cards. tioned the heads in a dedicated landing diagnositics, and a Novell Netware net- There is an approach to make it possi- zone where data is not written or read. work driver. ble to use a full -length card in front of The "park" program, moving the heads The owner's manual was unusually OnBoard (or any other hard -disk card, altogether away from the media, goes complete. In addition to lucid instruc- for that matter). Just move the internal farther to avoid any possible damage, tions, with print in two colors, the manu- speaker's location to another area (where said the company spokesman. facturer took great pains in providing in- a half -length diskette drive controller We did handle the card kind of rough- structions in how to set up OnBoard to card is usually plugged in) and plug the ly, jarring the computer many times, in a work with a variety of computers that hard -disk card into Slot 1, which is the pulling the card and plugging it back the have various hard -disk drive configura- expansion slot farthest from the power number of times without parking running tions. Hence, if someone has, say, a supply. This way, the extra width of the heads, but the thing just kept We also used a utility 10 -MB drive that was standard with XT card's drive extends towards the case's without a problem. models for some time, and needs more end, making it possible to mount a full - data storage, he doesn't have to dump length card in Slot 2. Maynard not only (Continued on page 81)

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 33

www.americanradiohistory.com Project An Audio /Video Distribution Amplifier

This device eliminates signal-loss problems usually encountered when trying to interconnect a TV receiver, one or more VCRs and similar products into a single video entertainment system

By Jack Cunkelman

The variety of video equipment used in home -entertainment systems has multiplied amaz- ingly over the past ten years. People now have several VCRs, video cameras, laser -disc players, satellite TV receivers, cable TV converters, and computer video monitors, for example, as well as stereo hi -fi components. All of these sources are usually separate units that must be interconnected to make up a "system." How to do this without loss of any of the performance quality designed into each unit, which can cause a "grainy" picture or severe reduction of audio high frequencies, can be a real problem. A functional solution is building (and using) the Audio/ Video Distribution Amplifier to be described. The A/V Amplifier is a relatively simple, low -cost homebrew project that counters signal losses that can you can receive them with the MTS method for the various devices used deteriorate reception. Additionally, stereo incorporated into newer TV in home video entertainment systems it offers an orderly way to intercon- receivers. If you need more audio has been to distribute the signal as r -f nect a bevy of video products. It pro- and video lines than provided in the on a coaxial cable. The r-f signal con- vides three independent video and basic unit, you can build more Dis- tains both video and audio informa- three independent audio outputs (all tribution Amplifiers as needed, just tion that is modulated on an r -f car- isolated from each other) and fea- as inexpensively. rier for delivery to the antenna termi- tures stereo sound for each of its nals on a typical Interconnections TV receiver, which audio outputs so that it's ready to ac- is tuned to the particular channel de- commodate stereo TV broadcasts if The most common interconnection signated for its reception. Modula-

34 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com stallation that has more than three video devices that have to be connected to form a system, it may not even be practical. Every time the audio and video signals are combined by a modulator and are then demodulated, a little of WITH "Y" CORD (A) NORMAL INPUT VCR OR MONITOR (8) 2 INPUTS CONNECTED the signal quality is lost. If the signals are modulated and demodulated sev- normally 2 volts across 75 ohms of Fig. 1. Outputs from video equipment are eral times, deterioration becomes impedance causes a 1 -volt sig- impedance. Matching such outputs with the same noticeable. Consider that a TV pro- as in the upper illustration. If nal to be delivered to the equipment being driven, gram recorded from a cable TV were to be connected in two devices, both with an input impedance of 75 ohms hookup has undergone the modula- parallel (as would be done with a Y connector) across the 75 -ohm source imped- tion /demodulation process three ance, each would receive only 0.66 volt of the signal, as in the lower illustration. times before you finally view it. If you were to compare the original with the taped program, you would in tion is accomplished by the same the signal to be on by setting a switch observe an obvious degradation process TV stations use to send their in the VCR). The TV receiver, a sec- the taped version. program audio and video signals ond VCR or whatever other device is If you were dealing with a stereo to you. receiving the signal demodulates the audio signal, you would discover A VCR also applies this modula- r -f signal to extract the original audio that one of the two audio channels is tion process to the audio and video and video information so it can deal missing because the standard modu- one signals from tape. This combined r-f with them separately. lation process can deal with only is desir- signal usually exits the VCR at a fre- The r -f /coax cable method of in- channel of audio. Thus, it quency that can be tuned to the TV terconnection is the most straight- able to manipulate and distribute the receiver by setting its channel selec- forward and popular in current use. audio and video signals separately. have become more tor to either channel 3 or channel 4. However, it is not necessarily the As consumers de- (You select which channel you want best. In fact, in a typical home in- quality- conscious, equipment

+12V C2 o 0.1µF {f-- R5 1.8K R6 2.2K 01 R10 2N3053 -075 D1 R4 1N914 R8 R11 200 2.7 A 75

= 3 R9 D2 Cl IC1 2.7 R12 R2 1N914 22µF 4.7K CA3100 75 In> ) 02 Outputs 2N4037 R1 R3 R7 75 2.5K 2.2K C3 0.1µF {(--a. o -12V

Fig. 2. The video portion of the Distribution amplifier.

ELECTRONICS / 35 Say You Saw It In Modern Electronics March 1987 / MODERN

www.americanradiohistory.com signers have devised equipment that allows them to deal with audio and NOTE: R3, R4 = Dual 100K video signals separately. potentiometer Most home VCRs have separate video and audio input and output CH. A Out 1 jacks, as well as the usual cable con- R9 nector for the modulated r -f signal. 1K The new generation of TV receiver/ CH. A monitors now have audio video R1 Out 2 and 47K inputs, as well as the usual r -f anten- CH. A In na terminals. Home video cameras R3 CH. A Out 3 also have individual audio and video 100K R15 outputs. The main problem, then, is (see note) 300 in distribution of video signals to all of the devices that may be in a home video entertainment system.

The video output from a VCR, for CH. B

Out 1 example, consists of a 2 -volt, R16 75 -ohm signal (Fig. 1). The input of R10 300 the receiving device (say, a TV 1K CH. B monitor or another VCR) presents R2 Out 2 47K C6 R17 75 -ohm load to this signal. This is the CH. B R8 1/25532 100pF 300 terminating input. When both ends In R4 CH. B are connected, 1 volt of the 2 -volt 100K Out 3 signal appears across the source ter- R18 (see note) 300 mination and the remaining volt appears across the input termination of the destination device. If you were to connect two inputs to this one out- Fig. 3. The audio portion of the Distribution amplifier. put, such as is done when you use a "Y" connector, the level across each input would drop to 0.6 volt. The re- put is terminated. Terminations are rate isolated audio and video lines to sult is a noticeable degradation in required to keep reflections off the each device is a good idea. Also, picture and /or sound quality. interconnecting coaxial -cable line. driving the audio interconnect lines Each receiving device requires its While audio distribution is not as from a low- impedance source allows own separate feed because every in- critical in this respect, running sepa- you to use longer interconnect cables.

T1 IN IC1 OUT +12V s1 F1 7812T OPTIONAL 24V . Cl . C3 C.T. T 2000pF COM 6.8µF RECT1 T II

INI IC2 I OUT 7912T o 12V . C2 2000µF COMI 117Vac I

Fig. 4. A single bipolar power supply suffices for powering the Distribution Amplifier's audio and video circuits. IN REGULATOR PIN - OUTS

36 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com PARTS LIST Video Amplifier R1,R10,R11,R12 -75 ohms bayonet -type fuse holder or chassis - Cl ,C2-0.22-AF Mylar capacitor R2 -4,700 ohms mount fuse block; 4 -place phono- C3,C4- 0.1 -µF disc capacitor R4 -200 ohms jack strip for video input and outputs 100 25 -volt radial -lead C5,C6- -µF, R5 -1,800 ohms (Radio Shack Cat. No. 274 -322A or electrolytic capacitor R6,R7 -2,200 ohms similar); 8 -place phono -jack strip for ICI -5532 dual operational amplifier R8,R9 -2.7 ohms audio inputs and outputs (Radio /4 tolerance All resistors'' -watt, 5% R3 -2,500 -ohm, linear -taper Shack Cat. No. 274 -370 or similar); carbon film potentiometer metal enclosure (Radio Shack Cat. R1,R2-47,000 ohms No. 270 -274A or similar 8V4"W x R5,R6- 560,000 ohms Power Supply & Chassis 6'/, "D x 3'/,6'ß-I box); ac line cord R7,R8 -330 ohms C1,C2- 2,200 -µF, 25- volt axial-lead with plug; small -diameter coaxial or R9,R10 -1,000 ohms electrolytic capacitor shielded cable; clip-on heat sinks for R11,R12 -2,200 ohms C3,C4- 6.8 -µF, 16 -volt tantalum regulators in power supply (option- R13 thru R18 -300 ohms capacitor al); insulated standoff post; pointer - R3,R4 -Dual 100,000 -ohm, linear - F1 -0.5- ampere slow -blow fuse type knobs for controls; labeling kit; taper potentiometer ICI -7812T + 12 -volt regulator clear spray acrylic (see text); % "metal Audio Amplifier IC2 -7912T 12-volt regulator spacers (12); machine hardware; Cl- 22 -µF, 16 -volt radial -lead RECT1 -100 -volt, 2- ampere bridge hookup wire; solder, etc. electrolytic capacitor rectifier Note: Etched, drilled and plated printed - 0.1 -µF disc capacitor S1 -Spst toggle or slide switch C2,C3- circuit boards are available from Jack (optional) D1,D2 -1N914 diode Cunkelman, P.O. Box 397, Milford, OH 1- -tapped IC1- CA3100 BiMOS operational T1 -24 -volt, ampere center 45150: No. V11 video board for $7.00; amplifier transformer No. All audio board for $7.00; No. PSI 1 Q1- 2N3053 pnp transistor Misc.- Printed -circuit boards or per- power -supply board for $5.00. Add $1.00 Q2- 2N4037 npn transistor forated board and suitable soldering P &H per order. Ohio residents, please for sales tax. All resistors 'Y4 -watt, 5% tolerance or Wire Wrap hardware; sockets add 6% state carbon film ICs in audio and video amplifiers;

If you have audio and video jacks this arrangement is that distribution sponse and should not be substi- on your home -entertainment equip- amplifiers are designed to provide tuted. Transistors Q1 and Q2 boost ment (these are usually coaxial pho- multiple isolated outputs of an input the output current from IC/. Feed- no jacks like those used on audio signal. By making the circuits sepa- back is provided by RS to give the cir- equipment), you may want to utilize rate, it is relatively easy to main- cuit linearity and stability. them and the Audio /Video Distribu- tain isolation. Circuit gain is determined by the ra- tion Amplifier to be described to In any distribution amplifier, the tio of R4 to RS. The values of these configure your system. The Distribu- signal at the output is at the same resistors were chosen so that a 1 -volt tion Amplifier's three video and level as the input signal. The signal across input terminator R1 pro- three audio outputs (the latter with Audio /Video Distribution Amplifi- duces a 2 -volt signal at point A when two stereo channels) should allow er described here takes this into ac- R3 is set to the middle of its rotation. for maximum flexibility. The notice- count. It also features variable gain Because point A is a very -low im- able increase in audio and, especial- for those situations where there is pedance, resistors R10, R11 and R12 ly, video performance will make too great or too little a signal level for serve as the sending -end terminators building and using this project a optimum viewing and listening. Thus, to provide the 75 -ohm output imped- worthwhile effort. it eliminates the need for an extra sig- ance required to drive the coaxial in- nal attenuator and /or booster. terconnecting cables. Since point A Three amplifiers are provided: one is an ideal (almost 0 -ohm) voltage About the Circuit video and two audio. The video por- source, whatever occurs at the out- Three separate circuits make up the tion of the circuit, shown in Fig. 2, put side of any one of the sending - Audio /Video Distribution Amplifi- utilizes an RCA CA3100 BiMOS op- end terminating resistors has no ef- er: the video, the audio and the erational amplifier (IC/). This op fect on the output sides of the other power supply. The basic reason for amp has excellent high- frequency re- two sending -end terminating resis-

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 39

www.americanradiohistory.com tors. Hence, each output is isolated from the others. TECHNICAL SPECIFICATIONS Bypass capacitors C2 and C3 are Audio Amplifier required to prevent oscillations. Distortion (at -4 dBV) < 0.02% Nominal bandwidth of this amplifier Signal -to -noise ratio > -70 dBV Frequency response is 10 MHz. So high- frequency oscil- 20 Hz to 30 kHz, ±0.1 dB lations could be a problem if these Clipping point +9 dBV bypass capacitors were not used. Shown in Fig. 3 is the audio por- Video Amplifier tion of the Distribution Amplifier. Differential phase <0.5 degree Differential gain See photo This circuit is built around 5532 dual op amp /C/, which handles the two VIDEO COLOR -BAR RESPONSE channels of audio in a single inte- GRA!. A grated- circuit package. Since both ,o.,r,,. channels operate identically, we will . discuss only one. Op amp ICI is a low -noise device that is optimized for audio applications. The input impedance of this II 11. 11i>}.ï"m': Distribution amplifier is 47,000 ohms, which is set by R1. The gain of IC1 is set by the ratio of R11 to R9. With GAIN control R3 set at its middle of rotation, the signal level at VIDEO DIFFERENTIAL point A is the same as the input sig- GAIN VIDEO MULTIBURST RESPONSE nal's level. This is different from the video Distribution Amplifier because the impedances of the loads connected to the outputs (the inputs RECT1 is then filtered to clean dc by board measures 21/2 "- square. What- of a VCR, for example) are usually Cl and C2 and is regulated at + 12 ever wiring technique you use, the 10,000 ohms or greater so that there and -12 volts dc by ¡Cl and 1C2, re- circuits can be built on boards of is no drop across 300 -ohm output spectively. Capacitors C3 and C4 these dimensions. All wiring to and termination resistors R13, R14 and serve as bypasses that prevent un- from these boards should be done R1.5. (Note: R3 and R4 is a ganged wanted oscillations. POWER switch neatly to avoid unwanted oscilla- dual -potentiometer, which allows S1 is an option. tions and crosstalk. Also, use sockets the gain of both audio channels to be for the ICs on the video and audio adjusted simultaneously.) Construction boards, but not on the power -sup- The low output impedance of the ply board. Distribution Amplifier allows you to Since the circuitry for all three sec- Wire each board exactly as shown make long runs to other equipment tions of the Audio /Video Distribu- in Fig. 6, working on only one board with no loss of high frequencies. tion Amplifier is fairly simple, any of at a time so that you do not make any Note once again that the + 12- and a number of traditional methods of component errors. Install only the - 12 -volt power buses are bypassed wiring can be used to build the proj- sockets for the ICs on the audio and by C3 and C4, respectively, to pre- ect, though printed- circuit wiring is video boards -not the ICs them- vent unwanted oscillations. preferable. If you wish, you can fab- selves; these will be installed after A single bipolar power supply suf- ricate your own pc boards, using the you make voltage checks. Install and fices for both audio and video por- actual -size etching- and -drilling art- solder into place the resistors, fol- tions of the Distribution Amplifier. work in Fig. 5. Alternatively, you lowed by the capacitors (observe po- The circuit for this power supply is can purchase ready-to -wire boards larity with the electrolytics). When shown in Fig. 4. After 117 -volt ac from the source given in the Note at wiring the video board, make sure line power is stepped down by T1 to the end of the Parts List. you install the transistors in the pro- 24 volts ac, it is rectified to pulsating The audio and video boards are per locations and that you observe dc by bridge rectifier RECT1. The both the same size, measuring 3'h " proper basing. Also, make certain 24 -volt pulsating dc output from x 21/2 ", while the power -supply that the diodes are properly oriented.

40 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com -12V +12V -C3- -C2-

-R5- -R6- D1- - R8- R9- - Output -R7-

-12V Channel A Channel B GND outputs outputs -C3- I i I II o n aD

+ U U III " I i I

-R11- -R12- a ¢- U -R9 -R10- -R7- -R8- __J Channel B Channel A R6- -R5- - input input -R1- U -R2-

1' IC1

RECK ncaa l +12V -C3- OUT - ac Video GND coel - nr. Audio I IN I --12V

IC2

Fig. 5. The actual -size etching -and-drilling guides (left) to use if you plan on fabricating your own pc boards.

Fig. 6. Wiring guides (above) for the pc boards. These guides are also used to lay out circuit assemblies wired point -to -point with solder or Wire Wrap hardware.

1987 MODERN ELECTRONICS / 41 Say You Saw It In Modern Electronics March /

www.americanradiohistory.com Similarly, make sure the diodes are properly oriented, and make sure the regulators are installed in the appropriate locations, also properly based, on the power -supply board. Ditto for the bridge rectifier. If you are using perforated board, arrange the components on the boards in the same patterns and orientations as for the pc boards. Use #22 solid hookup wire to interconnect all components. Route the wiring as directly and make it as short as possible. Referring to Fig. 7, place the circuit -board assemblies inside the enclosure, in the locations shown and determine how long the wires that interconnect them must be. Make a note of the lengths needed and where Fig. 7. Follow this assembly layout inside the enclosure to avoid interference be- they are to be installed. Remove the tween the power transformer and the audio and video circuits. circuit -board assemblies from the enclosure. Prepare the wire lengths needed. Then install and solder them into place. Note that there are two Tightly twist together the shield and Q2 on the video board. The reg- + 12 -volt and two 12-volt output wires and sparingly tin with solder. ulators on the power -supply board pads on the power -supply board, one Do the same for the fine wires in the (ICi and 1C2) run warm when the set each for the audio and video am- inner conductors. Plug one end of project is operating but do not re- plifier circuits. each of the prepared cables into the quire heat sinking. If you feel more At this point, there should be no "input" holes on the audio and vi- comfortable with heat sinks, how- wires in the holes for the GAIN con- deo boards (shields to ground or ever, you can bolt onto the regula- trols or the inputs to and outputs common). Solder the connections in tors small ones. from the audio and video boards. all six locations. The other ends of The enclosure for the project is not There should also be no wires in the these cables and the previously in- critical. Only two requirements must 24 -volt ac and center -tap (Tl secon- stalled wires will be connected later. be met by it. One is that it must be dary) holes in the power -supply cir- Now remove '/, " of insulation large enough to comfortably accom- cuit board. from both ends of a 1'/ " length of modate the three circuit -board as- Prepare 13 8 " lengths of hookup hookup wire. Connect and solder semblies, power transformer, Pow - wire by removing /,"'' of insulation one end to a No. 6 solder lug. Plug ER switch (if used), GAIN controls, from one end of each. Plug the pre- the other end into the center -tap fuse holder and the input and output pared ends of these wires into the (C.T.) hole in the power -supply jack assemblies. The other is that it output and control holes in the audio board and solder it into place. must be metal -not plastic -so that and video boards and solder the con- When you are finished wiring the it fully shields the circuitry from elec- nections. When you are done, there boards, carefully inspect them for trical noise. should be 10 wires attached to the poorly soldered connections and sol- Machine the enclosure as needed, audio board and 3 wires attached to der bridges, the latter especially be- basing your layout on that shown in the video board. tween the closely spaced IC pads. If Fig. 7. The arrangement shown as- Prepare both ends of three 7 %" you suspect a connection, reflow the sures that there will be no interfer- lengths of small- diameter coaxial or solder on it and, if necessary, add ence between the power transformer shielded cable. To do this, remove 1 " more solder. and the audio and video circuit of the outer plastic jacket, separate Flip over the boards and double boards. Use the boards and power the shield back to the cut line, and check all components for proper val- transformer themselves as templates strip "of insulation from the center ues, locations and orientations. Clip conductor at both ends of the cables. small heat sinks onto the cases of QI (Continued on page 86)

42 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com ----.11111111111111/ panel control knob make tuning easier respond like thousands of other Now! In America than ever before. There's even a real monitor users the world over, we'll be 48 For the first time, the AR2002 is time clock with backup, a signal shipping you an AR2002 within UPS for only $455. available in the U.S.A.! Acclaimed strength meter and a front panel head hours by surface worldwide for its full spectrum phone jack. Plus, programmable Plus we pay all freight and handling our coverage, its superior sensitivity, search increments, a laboratory charges. Remember to ask about excellent selectivity and convenient, quality BNC antenna connector with custom test and triple extended buyer our compact design; it has all the features switchable attenuator, full memory protection warranty plans, and AC option. If you're not a sophisticated and discerning public backup, and power cords for or express shipping return your service band radio user desires. DC operation. A professional quality satisfied within 25 days, refund purchase Experts in Europe, and around the swivel mount telescoping antenna is AR2002. We'll your world report excellent performance in also supplied. and return shipping costs. There are independent lab tests. For example: no catches, no hidden charges. sensitivity across all bands will ...And More! typically exceed .3 microvolts in NFM. The AR 2002 And now the AR2002 is available to Every AR2002 has a special connector The Professional Monitor Receiver you exclusively through this offer. on the rear panel. It interfaces to our custom RC -pack. A little device that Peformance Above makes the AR2002 controllable by ANY computer with an RS -232C port. and Beyond The possibilities that result from this You'll hear signals from 25 through option are nearly limitless. In effect, 550 MHz, plus 800 MHz through 1.3 virtually your only monitoring COMMUNICATIONS GHz. In any mode: narrow band FM, constraint will be your imagination. Monitor Division wide band FM, or AM. Search 22511 Aspan Street. Lake Forest. CA 92630 -6381 through entire bands, or enter Yet Convenient to Own Call Toll Free 800 -445 -7717 frequencies into any of 20 MasterCard selected VISA Visa and memory channels. The sidelighted The AR2002 is available exclusively COD slightly higher - LCD gives full information on status through us so call us direct, TOLL - In IN 317- 842 -7115 Collect and programming. Profession quality FREE. We'll be happy to answer any 2 lbs., 10 oz.) hinged keys and a digitized front questions you may have. And if you (7'/8 "D x 55/1e "W x 31/8 "H Wt. CIRCLE 49 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 43

www.americanradiohistory.com All connections needed to cascade the two counters that add eight address lines are available at the Pro- grammer's PERSONALITY socket. One required change in the original circuit is the conversion of the 24 -pin sockets to 28 -pin sockets that can accommodate 64K 2764 and 128K 27128 EPROMs. The expansion board that adds the extra eight lines mounts over the EPROM Programmer's main board by plugging into the existing ZIF MASTER, PROGRAMMING and PER- SONALITY sockets. The add -on board is cut to expose program data LED hex displays DIS5 and DISE, as well as address displays DISI, DIS2 and DIS3 and locates two more displays to the left of the latter. The quick -lock /release action of the ZIF sockets on the original Programmer allow the retrofit board to be con- veniently installed and removed as you change from one type of EPROM to another. Locking the expansion board into the three ZIF sockets makes it an in- tegral part of the original EPROM Programmer. A switch on the board Stand -Alone lets you change the programming voltages as required for 2764 and EPROM Programmer 27128 EPROMs. Shown in Fig. 9 is PARTS LIST C18,C19,C20-0.1 -µF capacitor (Part 2, Conclusion) D14- 1N4001 rectifier diode DIS6,DIS7 -TIL -311 LED hex display (Texas Instruments; available from Retrofit module plugs into the basic Jameco) Programmer to allow programming IC18,IC19- 74LS193 4 -bit up/down of counter 64K and 128K EPROMs S6 -Dpdt slide switch (No. 201 M2QE, available from C &K Components SO4,SO5 -28 -pin ZIF Wire Wrap By Walter W. Schopp address lines limited the project to socket (Textool No. 228 -3345; avail- use with 32K- maximum devices. able from Jameco) Last month, we presented de- This month, we present an upgrade S06 -24-pin Wire Wrap IC socket tails for building a sophisti- retrofit board that expands the origi- (see text) cated stand -alone EPROM nal Programmer's number of ad- Misc.- Printed -circuit board; sockets Programmer capable of program- dress lines to 20. This brings the total for DIS1, DIS2, IC18 and IC19; two ming many popular 16K and 32K count up to FFFFF (1,048,276) to 24 -pin Wire Wrap sockets for interconnect pins (see text); hookup erasable programmable read -only permit programming and reading wire; up solder; etc. memory (EPROM) devices. Its 12 to 128K EPROMs.

44 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com Project

IN PROGRAMMER O SO1 A

SO2 IN PROGRAMMER O

1-1

)1-0 O n co m

o o

m S03 IN PROGRAMMER

with - Fig. 9. Schematic diagram of retrofit circuit that converts original EPROM Programmer for use large capacity 64K and 128K EPROMs.

1987 MODERN ELECTRONICS / 45 Say You Saw It In Modern Electronics March /

www.americanradiohistory.com the complete schematic diagram of the add -on module. Construction As with the circuitry in the basic Pro- grammer, printed- circuit construction is recommended for the add -on module. Though there are a number of wire jumpers on the retrofit board, the expansion adapter can easily be assembled on a single -sided pc board, the actual -size etching - and- drilling guide for which is shown in Fig. 10. Etch and drill the pc board and trim it as shown so that the cutout areas will give access to DIS1, DIS2, DIS3 and SS. Place the ready -to -wire board component side down on your work surface and, referring to Fig. 11, plug the pins of standard 24 -pin Wire Wrap sockets into the holes provided for them at the SO4 and SOS socket locations. Note that there are two columns each of 12 and 14 holes in both locations. Make sure you install these sockets in the 12- hole -not the 14- hole -columns through the bottom of the board! Tack solder diagonally opposite pins on each socket to the copper pads. Turn over the board and make sure Fig. 10. Actual -size pc etching -and- drilling guide. all pins in both sockets go all the way into the holes and are flush with the top of the board. the copper pads. Then install and that they sit solidly on the top of the Flip over the board and solidly sol- solder into place standard sockets board before soldering any pins to der all pins of both sockets to the for IC18, IC19, DIS6 and DIS7; ZIF the copper pads on the bottom of the copper pads. These connections sockets for SO4 and SOS; and a stan- board. Save installation of the ICs must be mechanically as well as elec- dard 24 -pin socket for S06. If you and LED hex displays for last. trically secure. Carefully cut through wish, you can use a ZIF socket for After all wiring shown in Fig. 11 is each pin of both sockets as close as S06, though this is not necessary. completed, flip over the board. Trim possible to the socket bodies -not Note once again that certain pins the pins of SO4 and SOS -but not the board -and discard the sockets. are absent from the LED hex dis- S06-close to the board. You must From here on, as you work with the plays and that no board holes are now trim all pins in the SO4, SOS board, be careful to avoid bending provided for them. Therefore, as and S06 locations so that they pro- any the pins. of was done in Part 1 for DIS1 through trude a uniform %" from the bottom Install and solder into place the DISS, clip off the pins of the DIS6 of the board. An easy way to do this wire jumpers at the locations shown and DIS7 sockets close to the molded is with a % length of small- diameter in Fig. 11. You can use either insu- bodies for those locations where no rigid tubing. Simply slip the tubing lated or bare solid hookup wire for board holes are provided. Also, over each pin in turn and trim flush the jumpers. Next, install the three when installing the ZIF sockets, or- with the top of the tubing (see Fig. capacitors, the dpdt switch and di- ient their lock /release levers toward 12). When all pins have been trimmed, ode. Make sure you properly orient the bottom of the board. Push the the diode before soldering its leads to SO4, SOS and S06 sockets down so (Continued on page 82)

46 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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CIRCLE NO. 180 ON FREE INFORMATION CARD

www.americanradiohistory.com Project The Ringer

A solid -state telephone bell replacement and stand-alone incoming -call annunciator

By C.R. Ball, Jr.

Several new integrated- circuit ringers that can be adapted by hardware hackers to telephone applications have been introduced by Motorola. With these ICs and just a few components, you can build a module that replaces the bell in a conventional telephone, or house the circuit in a small plastic box so that it can be used as a stand- alone incoming -call annunciator with or without having a telephone handy. Since the ICs can drive low - current optical isolators and relays, the Ringer accessory to be described can even be used to power distinctive annunciators for outdoor use, pro- Ringer installed in place of standard bell inside a telephone. vide a visual indication of an incoming call, and turn on electrical devices as a security measure. the same in all three cases and is illus- drive a piezoelectric buzzer or other If you have more than one tele- trated in the block diagram in Fig. 1, device that has a current drain of less phone line coming into your home or along with the device's pinouts. The than 20 milliamperes. office, you can have different tones differences between the three chips Input signal detection circuitry for each line simply by changing ICs, ac- are in the base frequencies and the tivates the tone ringer output when resistor /capacitor values, or piezo- values of capacitance that are used the ring signal input (tip to ring on electric buzzers. The input impe- (see Table 1). the telephone line) exceeds the dance of the Ringer meets all Bell Because the Ringer is powered di- threshold determined by the values and EIA standards and fully com- rectly from the telephone line, it nev- of R3 and C2. When the potential plies with Part 68 of the FCC Rules er needs batteries or ac line power to across the R3 /C2 network exceeds and Regulations when built as de- operate. The complete circuit for the 1.2 volts dc, the threshold compara- scribed here. The stand -alone ver- project is shown schematically in tor enables the tone ringer. Trans- sion uses 4- or 6- contact modular Fig. 2. (Refer to Figs. 1 and 2 for the ients produced by pulse -dialing tele- connectors for simple installation. following description of circuit oper- phones do not charge C2 to a level ation.) When About the Circuit a call comes in, the ac sufficient to activate the tone ringer. ring voltage that appears across the Once the tone -generating circuit Any one of three different versions LI and L2 (ring and tip) wires of the has been activated by the threshold of the Motorola IC tone ringer chip telephone line is rectified by a diode comparator, oscillator, frequency can be used in the Ringer. All three bridge inside the MC34017 -x chip divider, warble frequency divider have basically the same circuitry, used for UI and is filtered by exter- and push -pull output stages are en- with each distinguished by a differ- nal capacitor C4. From here, it is abled. The oscillator frequency is di- ent suffix number. The circuitry is used to power a tone generator and vided (the ratio depends on the spe-

48 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com Diode R1 Cl bridge Tip >-I( o AG, it Input current I N NI N Ni mirror - X A- C4 8 ()AC, RI 4 Ring} I1 SCR 22V R01 2 TRANSIENT Piezo CLAMP Bias (( sound R020 3 element 7 RG Push -Pull 1 1 = output buffer

Tone Threshold ,RS 5 frequency comparator divider R2 C2 6_RC Oscillator Warble I R3 C3 T., frequency REF divider

Fig. 1. Internal details and pinouts for Motorola's tone -ringer ICs.

cific version of the IC used for U1) to and can directly drive piezo trans- Table 1. IC Frequency Specifications provide the basic tone, which is mod- ducers, optical isolators and low - ulated by the warble tone. current relays directly. If you wish to IC Frequencies (Hz) Value of The warble frequency of 12.5 kHz use other than piezo annunciators, Type Base Warble C3 (pF) is common to all three versions of the an optoisolator interface is recommended to assure that the project op- MC34017-1 1,000 12,500 1,000 Motorola chip. The base frequencies MC34017-2 2,000 12,500 500 for each version are shown in Table 1. erates within the guidelines set forth MC34017-3 500 12,500 2,000 This circuit is capable of sourcing in Part 68 of the FCC Rules and Reg- or sinking up to 20 mA of current ulations that concern subscriber equipment connected to the telephone network.

C2l R2 Construction note) 2.2µF T+ 15K (see It is possible to assemble the Ringer on perforated board using point -to- C3 R3 point wiring and suitable soldering (See - 180K Table 1) or Wire Wrap hardware. However, GREEN Ring < 12, printed- circuit wiring is recom- 60 mended because of the close spacing ACZ RG RC RS of the modular connector pins and MC34014 -X the danger of producing solder 1 (See Table 1) bridges. You can fabricate your own -size etch- AC, ROI R02 RI pc board using the actual

2 3 R4 ing- and -drilling guide shown at the P1 10K left in Fig. 3. If you prefer, you can LI, RED Tip VOLUME a ready -to -wire board from R1 C4 purchase NOTE: 6.8K 5µF the source given in the Note at the J1 and J2 are end of the Parts List. used as a bell replacement. Note in Fig. 3 the small tab that ex- Fig. 2. Complete schematic diagram of Ringer. tends above the top of the guide. You

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 49

www.americanradiohistory.com PARTS LIST Table 2. Telephone Subscriber Line Specifications C1 -1 -µF, 200 -volt Mylar capacitor C2- 2.2 -µF, 16-volt tantalum capacitor Parameter* Value Condition C3 -See Table 1 C4 -5 -µF, 25 -volt tantalum or electro- Central office voltage 48 volts dc on -hook lytic capacitor (positive ground) J1,J2- Modular pc -mount jack (Berg Central office voltage 10 volts dc off -hook No. 66011 -001 or similar; available Central office voltage 105 volts ac, on -hook from Mouser corp., 2401 Hwy. 287 20/30 N., Mansfield, TX 76065) Hz ringing Subscriber PI -6 -volt piezoelectric buzzer (Proj- loop current 20 to 30mA off -hook, ects Unlimited No. 6A or similar) CO seizure R1-6,800-ohm, 'h -watt, 5% tolerance Subscriber loop resistance 0 to 1,200 ohms off -hook resistor * R2- 15,000 -ohm 1/2-watt, 5% tolerance All tip to ring. resistor R3- 180,000 -ohm, 1/2-watt, 5% tolerance resistor will include or omit this tab, depend- techniques are different for each R4- 10,000 -ohm pc -mount trimmer or ing on whether you panel -mount standard potentiometer plan to install the type of installation. Therefore, first (see text) Ringer in place of the bell in your decide whether you want to use the

U1 -See Table 1 present telephone (include) or house Ringer as a bell replacement or as a Misc. -Printed- circuit board; case for it inside a stand -alone box for an- stand -alone annunciator. stand -alone version of project (Radio nunciation purposes (omit). For bell replacement, do the fol- Shack Cat. No. 270 -221 or similar); You can mount the pc board as- lowing. Leave the tab on the pc spade bolt (see text); spade clips or sembly directly in place of the me- board. Wire the board exactly as stab -on connectors (see text); machine chanical bell ringer in a standard shown at the right in Fig. 3. Start wir- hardware; hookup wire; solder; etc. 500D (2500D Touch ToneTM) tele- ing the board by installing a socket Note: The following items are available from phone. If you plan to use the Ringer (or Molex Soldercons® ) in the U] Ballco Inc., P.O. Box 1022, Snellville, GA as 30278 -1022: pc board No. 851201 for an auxiliary device, trim the tab location. Do not install the IC in the $8.95 ppd; complete kit of components from the board to permit mounting socket until directed to do so. Next, for bell replacement, No. RNG -B, for inside a plastic or other weather- install the remaining components in $14.95 plus $2.50 P &H. Georgia residents, proof box that is only slightly larger their respective locations in the nor- please add state sales tax. than the board itself. Construction mal manner. Pay careful attention to

X RINGO TIPO JI O RI OCDD

P1 O O + .R;voL

Fig. 3. Actual -size etching -and -drilling guide (left). In- inside a telephone; omit it if project is to be used as stand- clude tab at top if project is to be installed in place of bell alone annunciator. Wiring guide for pc board (right).

50 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com the polarities of the piezoelectric tion is much the same with this ver- buzzer and electrolytic capacitors be- Wall jack sion as for bell replacement, except fore soldering their leads to the cop- for installation of the two modular per pads on the bottom of the board. jacks and how VOLUME control R4 is VOLUME control R4 mounts on the Telephone mounted. Here you mount R4 on top foil side of the board so that it can be optional of the board, adjacent to the piezo adjusted in the same manner as the buzzer. Two jumper wires, as de- original bell. Fig. 4. Connections for stand -alone tailed in Fig. 3, are also needed. annunciator. Remove '/. " of insulation from To mount the modular jacks, posi- both ends of two 6 "wires (preferably tion the pins in the holes and snap the color coded for easy identification). plastic retainers into the board. Then Plug one end of these wires into the devices, install Ul in its socket or solder the connector pins to the cop- "tip" and "ring" holes in the board, Soldercons. If you are using a sock- per pads on the bottom of the board. and solder both wires into place. Sol- et, make sure no pins of the IC fold Use extreme care when soldering der a spade lug or stab terminal, de- under the device or overhang the these very closely spaced pins into pending on the needs of the tele- socket before pushing it home. place. Once again, reserve installa- phone you have, to the free ends of For the stand -alone annunciator tion of UI in its socket or Soldercons these wires. Then install a spade bolt version, two modular jack positions until the last step in wiring /installa- in the hole marked with an X, using must be available to provide the tion and practice safe handling pro- No. 6 machine hardware. means for connecting the Ringer to cedures for MOS devices. Now, exercising standard pro- the telephone -line wall jack and a Drill holes in the case for mount- cedures for safe handling of MOS telephone, modem, etc. Construc- ing the circuit -board assembly and

+12V

NOTE: 117Vac Use low current (20mA) 12Vdc relay or buffer circuit. 1N4004 Wall jack Telephone

2.2K ROI )E) Ringer

1N4001 R02 >F)

+12V +5V to +12V

A D (B) (C) (D)

Fig. S. Various add -on arrangements for different annunciator applications.

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 51

www.americanradiohistory.com for access to the VOLUME control. Auxiliary For easier volume adjustment, you 0.1µF input might want to substitute a conven- To tional panel -mount potentiomter of wall jack the specified value for the trimmer control shown in the photos and con- Phones, nect it to the board with short lengths etc. of insulated hookup wire. Notches for the modular jacks can be drilled Fig. 6. Amplifier /speaker arrangement for using Ringer in high -noise applica- and shaped with a file or be punched tions. Warble tone is amplified and fed to trumpet speaker. out with a nibbling tool. Whichever version of the project you are assembling, it is imperative that you thoroughly clean the board connectors, which also depends on ring connections are reversed; after assembly. Use a flux remover manufacturer and date of manufac- though this does not matter for most for this step. ture. The corresponding terminals to automatic dialers and modems. Before putting either version of which the incoming telephone line the Ringer into service, it is a good connect inside your telephone will be Applications idea to test it. Do this by temporarily labeled with either "T" and "R" or There are a number of applications connecting one lead of a 4,700 -ohm "L1" and "L2." to which the Ringer can be put. The resistor lead to either the ring con- When connecting the Ringer, po- following detail a few of them: nection on the board and an ac line larity is not important for bell -re- Stand -Alone Auxiliary Ringer. cord with plug to the other resistor placement applications because the Here, the Ringer is used for remote lead and the tip connection on the ring signal is an ac voltage and a di- locations -such as a patio, a garage, board. Insulate both connections so ode bridge inside UI in the project etc. -where you might not have (or that you do not get an electrical takes care of managing polarity as want) a telephone but wish to know shock or damage the circuit. Plug the well as rectifying the ring voltage. In when a call is coming in. Install the line cord into an ac outlet. You stand -alone annunciator applica- Ringer as shown in Fig. 4. should hear the piezo buzzer sound if tions where modular jacks are in- Stand -Alone Loud Annunciator. everything is okay. If not, disconnect volved, polarity is very important. Use this arrangement for outdoors the line cord from the ac outlet and You cannot dial out on a standard rectify the problem. Touch Tone telephone if the tip and

Installation As a bell -replacement module, the Ringer can be mounted directly in Table 3. Network Progress Tones place the existing bell in a tele- of Frequency On Time Off Time phone. Some telephones have screw Tone (Hz) (sec.) (sec.) Condition terminals, others pull -off terminals. Dial 350 + 440* cont. N/A Off -hook Carefully disconnect the wires from Busy 480 + 620 0.5 0.5 Line busy the bell to the telephone network Ringback 440 + 480 2.0 4.0 Ring (there are usually four wires). Tight- indication en the screws if your telephone uses Network Busy 480 + 620 0.2 0.3 Network them. Remove the existing bell and circuits replace it with the Ringer. Some of congested the hardware may be interchange- Reorder Tone 480 + 620 0.3 0.2 Local able in this operation, depending on circuits the telephone's manufacturer and congested 1,400 + 0.1 0.1 Off hook the date of manufacture. Off-Hook 2,060 + beyond Connect the tip lead to the green 2,450 + time -out wire and the ring lead to the red wire 2,600 period coming from the telephone line. *Electronic Central Office These can be either screw or stab -on

52 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics www.americanradiohistory.com TRI -MODE CABLE TV DESCRAMBLER PARTS

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CIRCLE 65 ON FREE INFORMATION CARD

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Enhance vol I Companion Disk 19.50 Enhance vol II Companion Disk 19.50 Assembly CB Companion Disk 19.50 Applewriter CB ProDOS C. Disk 24.50 Assembled stand-alone annunciator. FREE VOICE HELPLINE VISA'MC SYNERGETICS Box 809 -ME Thatcher, AZ 85552 and high -noise areas. The voltage device simply by calling your home (602) 428 -4073 from RO1 and R02 that normally from wherever you happen to be. In CIRCLE 39 ON FREE INFORMATION CARD drives the piezoelectric buzzer is rec- this circuit, point E from the circuit tified, filtered and used to drive an in (A) is coupled through a 0.001 -mi- Need Quick optical isolator, as shown in Fig. crofarad capacitor into the "trig- Turnaround 5(A). Use of the optoisolator and re- ger" input of the 555 timer circuit, lay as shown ensure isolation of the point F goes to the timer circuit's on CRYSTALS? telephone line from the 117 -volt ac ground, and there is nothing con- line as per Part 68 of the FCC Rules nected to point A coming off the op- Try E.O.D. Our and Regulations. Fig. 5(B) shows an toisolator. Points C and D of the 555 (Emergency Order Dept.) optional circuit that can be installed timer circuit are relay outputs from between the + 12 -volt power bus and that circuit. and get collector output from the optoisola- When this circuit is installed, a call tor if more buffering is needed for replaced by you will turn on designated JAN QUALITY lay -drive circuits. An audio amplifi- lights or sound devices for predeter- and STABILITY er and speaker can also be used, as mined periods of time you select. shown in Fig. 6. The 555 timer block here represents a PLUS Low Prices! Stand-Alone Visual Annunciator. timer -driven relay circuit you build This arrangement is used for very separate from the project. For de- You benefit from 21 years of noisy locations, for the hearing im- tails on how to build such a manufacturing quality crystals circuit for industry, military services, paired and where audio annunciation and timing resistor /capacitor values, radio amateurs, citizen band is not acceptable, such as in record- see Forrest M. Mims III's 555 Timer and experimenters. ing studios, operating rooms, etc. A IC Circuits published by and avail- typical arrangement for this is shown able To Get Free Catalog from Radio Shack (specify Cat. in Fig. 5(C). Actually, though the No. 276 Call or Write -5010). circuit shows a 117 -volt ac line -pow- Other. Since the Ringer can be JAN CRYSTALS ered lamp, you could use a 12- or even powered from the 117 -volt ac line, it P.O. Box 06017 6 -volt dc source and lamp instead. can also be used to replace the an- Ft. Myers, FL 33906 Security. The circuit in Fig. 5(D) noying buzzer on a clothes (813) 936.2397 dryer. can be used to activate lights, a radio This is just one of the many non -tele- or some other electrical appliance or phone applications for this project. CALL 1- 800 -237 -3063 FREE (Except Florida)

CIRCLE 36 ON FREE INFORMATION CARD 54

www.americanradiohistory.com NEVI PRODUCTS (from page 15) Plan To Move? Let Us Know.

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Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 57

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More on Omnicrom; genlocking video images; v/f converters; the Postscript language; an easy printed- circuit process

By Don Lancaster ® ® ® Co m m ® m ® m ® ® ® Lots has been happening on the Omni - HSI CSO VOS CPF CVC COT CGD CV1 CV2 KLF OLF PIC VCC CVO GND OLE RMI ACF -YI RVC crom front since we last looked at this exciting new process that lets you cheaply MCy get full -color from the toner image pro- 378 vided by a copier or laser printer. First LIR HPF HV1 HV2 BG0 PIN GND 3/4 CPF CV1 CV2 RYC BYC RIN GIN BIN -YO CRO LVC CRI and foremost, the Kroy Sign Systems 16 17 18 19 20 people have taken over production, mar- 00000000000®000 keting, and distribution of this material Fig. 1. A Motorola integrated circuit for genlocking by synchronization. in the U.S. This should mean much better availability and considerably lower prices. The new name is "Kroy Kolor." There are also some new goodies now available that include binding and lami- genlock to watch nine channels at once. An educator might use genlocking to nating materials, plus all sorts of sign +5V SOT T;O CAS 0 AO Al A2 A3 A7 holders. For samples and more details on overlay computer -generated text over a all this, contact Randy Bailey at Kroy. full -resolution video picture. A scientist TMS4y 61 might do the same for crosshairs, image Quite a few Hardware Hacker readers eSIN SCL SDE D W RAS A6 AS A4 GND have been using a plain old iron to fuse processing, or feature identification. Ca- ble people routinely the Omnicrom sheets. To do this, you ei- use genlocking to overlay fixed ther work upside -down or else place a or crawling ads and public Fig. 2. A Texas instruments integrated sheet of paper or a muslin or cotton service messages. circuitfor genlocking by frame grabbing. pressing cloth between the iron and the In a TV studio, there are countless uses of genlocking. One oldest transfer sheet. I skipped this critical step of the and and ended up with a gorpy mess. neatest is the "chroma key" process that Two other tips: A clay- coated and saves having to make large color maps ly been complex but fairly cheap, there smooth paper works best, provided that and such. No , that weather turkey is not are all sorts of problems on a personal the toner itself will stick to the paper. An pointing to a map. He is pointing to a computer. Not the least of these is that obscure paper called "Paloma Matte" bright blue square on the wall. The map most personal computers do not use in- by Butler Paper performs very well. For is on a color slide. When the chroma key terlace and have standards different the sharpest image, be sure to quickly circuits see bright blue, they switch to the from broadcast -quality TV. Another separate the sheets after fusion. map. When they see an arm, they switch problem is providing the fast locking We'll look at another "mess with the back to the weather turkey. needed to track a VCR or other jittery toner" product that ridiculously simpli- Now, genlocking must be and should outside video source. fies hacker printed- circuit boards short- have been the centermost feature of all The second method is called "frame personal computers since day one. Yet, grabbing." With a frame grabber, you ly. But first ... . except for a limited genlock on the Ami- store an entire picture or two from the Tell me about genlocking. ga and a full genlock on some Sony mi- one system and play it back to the sec- crocomputers that are totally unknown ond. You can easily get from one set of Genlocking is the missing ingredient to outside of a TV studio, none of the more wildly different video standards to an- letting personal computers truly interact popular personal computers have very other, and no actual locking of the local with "real" video from a VCR, cable, much in the way of genlocking available. source is needed. This used to take a hu- CD disk, or studio. A genlock lets you With video on CD ROM just around the mongous and ridiculously expensive ana- synchronize and lock one video source to corner, this is totally inexcusable. log or digital memory. Today, of course, another so they can be superimposed, There are two main ways to handle large digital memories are trivial and windowed, or whatever. genlocking. With a true genlock you ab- nearly free. For instance, a home -video freak solutely and positively synchronize both Fortunately, there are at least two new might use his personal computer for ti- systems so that their scan rates, line posi- integrated circuits available that greatly tling, cuts, fades, and video wipes. A tion, and sync pulses are identical. simplify the genlocking process. And, couch potato might unknowingly use a While the true genlock has traditional- while not cheap, they are sanely priced.

58 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics www.americanradiohistory.com Motorola elected to go the true genlock From the computer side, this chip will do the job, giving you one bit per route with their MC1378 video synchron- looks and acts like a plain old 64K x 1 fairly large overlay pixel. If you want to izer. The pinouts of this chip appear in dynamic RAM. From the television side, get fancy and add finer resolution, gray Fig. 1; more details can be found in the the chip looks and acts like a high -speed levels or color, you set up multiple "pixel MC1378 data sheet, applications note, video shift register that holds an entire planes" as needed. For instance, 5 planes while and in graphics chip set data pack. line of pixels . Lines can be any multiple would get you one of 32 gray levels, This chip is basically a group of phase of 64 pixels, with 256 lines of 256 pixels 12 planes would let you pick any of 4096 lock loops (PL Ls) that first lock the verti- being a good hacker starting point. colors from an Apple Ilcs or similar cal sync pulses to each other and then Once during each horizontal blanking pallette. lock the individual horizontal scan lines. interval, a transfer command is given The usual way to get from noninterlace Special provisions are made to handle that moves the stored computer bytes in- to interlace is to write the same pixels to VCR jitter. For this chip to work, inter- to the line shift register. This is the only both the even and odd interlaced fields. lace and true NTSC timing would seem to time that any synchronization or arbitra- Denser and cheaper multiport video be essential, and the MC 1378 must take tion is needed between the computer and RAM chips and modules are just around over and substitute for the main system the television source. At all other times, the corner, and a $50 frame grabbing clock on whatever is doing the comput- the computer is free to write to RAM in genlock is not all that far away. Natural- ing. Thus, while it looks great on paper, I any order it likes, while the TV is free to ly, Modern Electronics is most interested don't yet see any obvious way to drop clock out the pixels at its chosen rate. in any construction project on a reason- this dude into an Apple or a Mac. One way to eliminate virtually all ar- able -cost genlock that would drop into a The second chip is the Texas Instru- bitration is to grab two frames and write mainstream -type computer. ments TMS 4161 Multiport video RAM, to the first one while you are reading the which is also available as 4 -bit and 5 -bit second. But a wait state generator can do What is Postscript? SIMM modules (TMS 4161 EP4 and the same arbitration faster and simpler. Postscript is the exciting new page -de- EP5). Figure 2 shows the pinouts, and A plain old blanking interrupt can some- scription language from Adobe Systems more tech details are found in TI's MOS times be used instead. that is fast becoming the de facto desktop Memory Data Book. These versatile mul- The number of chips you need depends publishing standard for laser printing tiport RAM chips are easily used for on how fancy you get. For a simple and typesetting. frame grabbing. black- and -white titler, one of these chips There are some outstanding advantages to Postscript. First and foremost, it is fun to use. In fact, the language is downright addictive. Postscript general- 0.01 µF ly lets you build much higher quality images much more flexibly and with incred- +5V ibly more power. Another major advantage is its device independence. This means that the very 0000 same textfile that is sent to a laser printer V CAP CAP GND can later be sent to a typesetting machine 10K AD654 for much higher print resolution.

NL UT GND RES IN Text and graphics can be mixed in any full 0 -10 kHz 0 000 1K 0 - 1 VDC manner anywhere on the sheet to the Frequency Voltage available resolution of the printer. You E Input can easily translate (move), scale (magni- Output 820Q fy or reduce), or rotate (twist) any image any way you want. You can even arbi- trarily map any text and graphics image CALIBRATE 500 S2 onto virtually any surface. As many of you already know, all of the Hardware Hacker graphics (and orig- Fig. 3. A simple voltage-to-frequency (v /f) converter circuit. inal text) is done using Postscript, work-

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 59

www.americanradiohistory.com HARDWARE HACKER...

ing from Applewriter on the IIGs and driving a Laserwriter Plus. (A) A toner image is Many hundreds of Postscript fonts are put on the TEC -200 now available, and any individual font sheet by using a can be shown any size from 3 point to copier or a laser 65,000 point. (72 points = 1 inch) Thus, printer. you can letter anything from a tiny model railroad sign to the name on your town's water tower, all with a single procedural font. Fonts can easily be stretched in any direction, leaned, outlined, clipped, or (B) The toner is then modified for other special effects. You transferred from WIN can even create your own very- high -qual- the TEC -200 sheet ity custom fonts. to a clean pc board Postscript has a very strong cubic using a hot iron. spline drawing and curve -tracing ability that can let you draw smooth and continuous curves six ways from Sunday. Pho- tographs and grays are easily included, although the final halftone quality de- (C) The pc board is then MN pends on the printer you have in use. etched, removing

copper from ( In fact, it is Postscript that has made all areas not covered by toner. Apple's Laserwriter Plus the best -selling printer in the world today. That is in dollar volume; the best selling printer in units sold is the Imagewriter. And yes, that's for all printers used on all personal computers! (D) After etching, the toner There are several good ways to get is removed using a started with Postscript. Two are the solvent or steel wool. Postscript Cookbook and the Postscript Reference Manual. If you can't find Fig. 4. How TEC-200 sheets simplify hacker fabrication of pc boards. these locally, I have a few extra copies on hand here. No, I didn't write them, but I sure wish I had. My own Postscript books are still in the works. You'll also er. I must get around 30 helpline calls a be used, and the technique works on just want to subscribe to Colophon, which is day requesting this. The language itself is about any personal computer. Adobe's free Postscript newsletter. in the public domain, so there's nothing Simple, cheap, and reliable V/F con- I have lots of free printed Postscript stopping you except for some personal verters in the past have been hard to find. demos and routines that you can run if time and effort. The obvious 555 timer route is difficult to you call or write. I've also got a fancy use accurately, especially with a ground - "Postscript Show and Tell" that now How can I measure voltage referenced input. And game paddle in- runs under just about any word proces- with my personal computer? puts are often hard to use, limited in sor, editor, or telecomm program, on range, and inaccurate. just about any personal computer. You The secret to measuring voltage with a Instead, Fig. 3 shows a brand new An- can also use the Hardware Hacker phone personal computer is to hang a beastie alog Devices chip called the AD654. This number for free Postscript help. called a "voltage -to- frequency convert- chip sells for around $4, gives you a 0 -to- If you want to tackle a really advanced er" onto an input port line and then use a 10 -kHz square wave output, and needs hacker project, just write and then debug machine -language software routine to only a single + 5 -volt supply. Resolution your own Postscript interpreter for the count the frequency for a tenth of a sec- can be 0.1 percent or better. Imagewriter or another dot matrix print- ond. Even a cassette input port can often Frequency is calibrated by changing

60 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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www.americanradiohistory.com the 500 -ohm trimpot. You can run at 100 The sheets possess the magic property for oversize artwork. Since fingerprints kHz by using a 1,000 pF capacitor in- that toner from a copy machine or a laser are a no -no, always handle the sheets and stead, but most personal computer soft- printer will loosely stick to them. What the pc material by the edges only. ware might not be able to keep up with you do is first copy the positive printed A brand new process? Hardly. Back in this higher rate. circuit image you want onto the Mylar the old days when Xerox machines were Two gotchas: For maximum accuracy, sheet. Then you place the imaged sheet, far too cumbersome and much too ex- you should have a 1,000-ohm source im- toner side down, onto an extremely clean pensive for plain old paper copies, they pedance; so you may want to drive this printed circuit board. You then apply a offered a similar process that directly from an input buffer of some type. And, hot iron to melt the toner. The toner will transferred toner onto an unetched pc don't forget that pullup resistor on the now stick to the copper much better than board, but as part of a room sized, ridic- open collector, or you won't be able to it does to the Mylar, so when you peel the ulously expensive and extremely hard -to- see the output square wave. Mylar off, a toner image stays on the use machine. Your software routine should count copper cladding on the pc blank. You can probably think of all sorts of changes on the port line for a tenth of a You next use the toner as an etch resist! other uses for this new material, since second or so. Note that all possible routes No photography, no silk screening, and you are now able to put a toner image on through the software routine must take no resist pens are needed at all. virtually anything that will sit still and exactly the same amount of time. Sometimes you will have to reverse the can stand brief application of a hot iron. Let us know what other uses you can image. To do this, just image onto Mylar Callouts for the other side of the printed - come up with for this extremely simple once, and then recopy from the Mylar, circuit board are one big possibility, measurement circuit. toner up and backed by a white sheet of while instant dialplates are another. Is there a simple process for paper. Note that the final toner pattern Laser printers work beautifully with on the copper pc material should have this stuff. You can even put Omnichrom making printed- circuit boards? black toner where you want copper to re- or Kroy Kolor over the final toner! There sure is. There's an exciting new main and clear where you want copper to Apparently, the material can stretch or product out called a TEC -200 transfer be etched away. deform slightly. This should not hurt use sheet available from Meadowlake. These Your copper pc material must be for most homebrew printed- circuit proj- are nothing but 8 % x 11 sheets of clear scrupulously clean. Scour it twice for five ects, particularly if you are careful and Mylar or whatever that may or may not minutes each time, using a chlorine practice a time or two on less -critical have some special coating on them. Cost bleaching cleanser from the grocery work. You should trim the sheet to with- is between 40 cents and a dollar per' sheet, store, and drying the board on a fresh in- in % " of the image before actually fusing depending on quantity. side turn of a roll of paper towels. Note the toner to the printed- circuit board. If Figure 3 shows how these TEC -200 that totally clean copper is wettable by any retouching is needed, the usual resist sheets work. The process is alike but dif- water, and you'll get a smooth and un- pen can do the job. ferent somehow from the Omnicrom or broken flow only when clean enough. The Meadowlake people have a special Kroy Kolor stuff. A reducing copy machine can be used Hardware Hacker offer of five sheets for

NAMES AND NUMBERS

Adobe Systems Kroy Sign Systems Maxim Motorola Semiconductor Powerconversion 1870 Embarcadero S120 Scottsdale Airpark 510 N. Pastoria Ave. Box 20912 2472 Eastman Ave. B -34 Palo Alto, CA 94303 14555 N. Hayden Rd. Sunnyvale, CA 94086 Phoenix, AZ 85036 Ventura, CA 93003 (415) 852-0271 Scottsdale, AZ 85260 (408) 737-7600 (602) 244-6900 (805) 658 -0933 (800) 521-4997 Analog Devices Meadowlake Precision Monolitbics Texas Instruments One Technology Way Lambda Semiconductors 25 Blanchard Dr. 1500 Space Park Dr. Literature Response Center Norwood, MA 02062 121 International Dr. Northport, NY 11768 Santa Clara, CA 95052 P.O. Box 809066 (617) 329-4700 Corpus Christi, TX 78410 (516) 757-3385 (408) 727-9222 Dallas, TX 75380 (800) 255-9606 (800) 232 -3200

62 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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Modern Electronics CITY STATE 76 N. Broadway, five bucks. Be sure to use the secret pass- Hicksville, NY 11801 DATE ZIP word "tinaja" with your order. And be sure to let me know what new and exciting uses you dream up for this great new process. ELENCO PRODUCTS AT DISCOUNT PRICES! What's new in tech literature? Analog Devices has an expanded and re- vised Analog -Digital Conversion Hand- book out. This well written hardbound textbook is a cut above your typical in- house "official company line" publica- tions. It is worth the $32 price. You can also get a free subscription to their Ana- log Dialog house organ by contacting 20 MHz DUAL TRACE OSCILLOSCOPE 35 MHz DUAL TRACE OSCILLOSCOPE Cammy O'Brian per the Names and Num- $349. MO -1251 $498 MO-1252 bers box. Top quality scopes at a very reasonable price. Contains all the desirable features. Elencos 2 year guarantee There's also a Linear and Conversion assures you of continuous service. Two 1x, 10x probes, diagrams and manual included. Write for specifications. Applications Handbook available from the Precision Monolithics people. While AUTO RANGING MULTI METER with TRUE RMS 41/2 t 180 the ap notes are aimed primarily at pre- CAPACITANCE and DIGIT MULTIMETER plus transistor tester MANUAL RANGING mium op amps, there's a lot of good info 31/2 DIGIT METER Model $135 id 7ÓÓÓ 28 FUNCTIONS here that can be applied to most any old $65V CM -1500 .05% DC Accuracy M-1180 . 7°/. ACY $36.95 bargain op amp. .1 % Resistance Reads Volts, Ohms, ACY $39.95 Current, Capacitors with Freq. Counter M-1182 .25°/. the latest in power -supply design, M1181 . 1%ACY $42.95 For Transistors & Diodes & Deluxe Case check into the Power Supply Circuits Lambda Semi- Handbook by Maxim, the GF -8016 Function Generator 10 MHZ OSCILLOSCOPE BREADBOARD conductor Applications Handbook, and with Freq. Counter Powerconversion magazine. a new product of my own, check $219 For Sine, Square. Triangle, the newly bound reprints from my Pulse, Ramp, .2 to 2 MHz Shown out 9434 Ask the Guru column. Frequency .1 thru 10 MHz As our usual reminder, this is your col- GF 8015 without Freq. Meter `169 10 MHz DC or AC $190 9430 1,100 pins $15 Triggered Sweep i 1 umn and you can get technical help per Calibrated Vert & Hor S.3000 9434 2,170 pins $25 Reads Volts P. Freq 9436 2,860 pins $35 the Need Help? box below. If you Triple Power Supply XP -660 haven't done so already, be sure to write 50 MHz LOGIC PROBE LOGIC PULSER or call for your copy of the brand new $14950 $23 $25 list. free stuff 0 -20V C 1A 0 -20V @ 1A 5V Q 5A LP -700 LP.600 Fully Regulated, Short Circuit Protected with 2 2 us pulse A Limit Cont. 3 Separate Supplies. 20 nec with memory NEED HELP? Phone or write your Hardware Hacker ques- 3 Amp Power Supply XP -650 DIGITAL LCR METER tions directly to: Model LC -1800 Don Lancaster Measures: Inductors $11950 Capacitors, Resistors $148 Synergetics - 'r 0-40V Q 1.5A Inductors 1 pH to 200 H Box 809 - r* 0 -20V Q 3A Capacitor. 1P/ to 200pf Resistor .010 to 20M Thatcher, AZ 85552 Fully regulated, short circut protected current ®d Ranges 6 Ind, 7 cap, 7 res limit control anadinni (602) 428-4073

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www.americanradiohistory.com 1 FOCUS IIIMINIMEME

MacPublisher II for Plenty of Desktop Publishing Power

By Mike Nikolich Feature Using The desktop publishing revolution has the Operational helped revitalize the personal computer Transconductance Amplifier market, and the computer that's prob- Discover the advantages of working with this ably owed the biggest debt of "thanks" often -disregarded member of the op-amp family for this is the Apple Macintosh. There is a wide variety of desktop publishing soft- By C. R. Fischer Offset 1 - NC NC NC null 8 ware available and in the works for the 2 7 +V + V Hundreds of uses for the Inputs ( Inputs IBM PC and its many compatibles, too, common operational - L. 6 Out + Out Amp as well as Apple II, Commodore and amplifier have been - V - 4 5 - Offset - V paraded Null throuuh pages of books (A1 (B) input Atari computers. and magazine articles during the Since oast 20 vears Strangely. Fig. 1. Pinouts of the ordinary 741 op amp (left) end many of us either run or belong though, several other devices in CA3080 operatanal transconductance amplifier (right). to clubs that regularly produce monthly the op -amp family have been Though both appear to be identical, note that the 741 has virtually ignored during the offset null. while the CA 3080 has bias input. bulletins, a desktop publishing software same period One of the lesser -known close cousins of package could be of value, giving the ma- the op amp is the operational C A 30 50 o p e r a t i o n a l Pin 5 is 0 7 volt above the terial a more respectable appearance. conductance amplifier, or OTA transconductance amplifier The negative supply potential. and This nifty little device has two devices appear to be input current must be limited to Moreover, most of you are in the busi- attributes that are difficult to identificat at first glance. but if less than 2 MA to avoid duplicate by other means you look closely you will notice damaging the IC. Note also that ness world and could well use a relatively Among the OTA s functions is that the CA3050 has an the CA3080 requires a a unique biasing input that allows amplifier bias input at pin 5. dual -polarity power supply that inexpensive in -house computerized pub- This the device to he used as a input provides a means for delivers no more than oI8 and lishing system. voltage-- or curent- controlled varying the conductance - I8 volts To remain on the safe resistor or switch. This feature (reciprocal of resistance) of the side. you should limit power If you're a Mac user, a good example makes it invaluable for varying CA3050 OTA by varying the supply potential to +15 and -15 an inexpensive, yet parameters in such analog c urrent -flowing into this pin volts. of powerful new circuits as waveform With no current, there is no Two other idwsyncrecies of desktop publishing software package is generators. amplitude and output whatsoever. while an the OTA are the input and output frequency modulators. input current of about 15 mA structures The inputs are Boston Software Publishing's MacPub- electronic musical instruments. produces maximum gain capable of handling only very etc While the operational lisher II. Its suggested list price is $195 (I transconductance amplifier resembles a typical operational got mine for $140). Fig. 2. A simple single -chip voltage controlled ampllffar, amplifier at first glance. there er vu. MacPublisher II is the souped -up ver- are some essential differences +V sion of MacPublisher, the desktop pub- that cannot be ignored if you R3 expect it to operate properly In 27K R5 lishing package that virtually got the this article, we will cover these 100K differences, show you some LEVEL whole ball rolling in the first place. (The basic circuits to get you started company was recently by experimenting. and talk about acquired Letra- some of the OTAs currently on R1 6 set, whose name is virtually synonymous the market Output Input with presstype.) 2MK 3 065V ac C A3080 Defining the OTA R4 R2 ti 1K j _1_22K Huge Documentation For purposes of this comparison. Fiq 1 shows the pmouts of the MacPublisher II is designed for the full ordinary 741 op amp and the gamut of Macs -from the tiny 128K ver- 48 / MODERI ELECTRONICS I September 1986 sion to the hard -disk models. Issues can be as long as 96 pages (limited by disk This remake of a September 1986 page from Modern Electronics is just a sample of what storage) and can include up to 256 arti- can be done with MacPublisher II, cles (each carried over, if desired, into 16 separate fragments up to 256 pages). The opening sequence is called "The anyone thinking of becoming an "instant When you open the MacPublisher II Ten -Minute Issue." Here, you are intro- expert " -be patient. This complex pro- package, one of the first things you not- duced to the basics of laying out articles gram takes time to learn well. ice about the documentation is that it is and cropping photos. From there, you One of MacPublisher II's major huge -nearly 300 pages! Despite this progress to "Basic MacPublisher" and strengths is that it puts the full control of massive amount of documentation, "Advanced MacPublisher." By provid- the program in the user's hands. This is BPSI makes it easy for you to produce ing this "stepping- stone" approach to both good and bad. The good is that it your first page in just a few minutes. This teaching the program, it's possible to provides you with a great deal of flexibili- is done through a three -tiered approach master MacPublisher II in a few days. ty in designing and laying out pages. The to teaching the software. However, there is one word of caution to bad is that a user must have a thorough

64 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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understanding of the program to take form manner, MacPublisher II includes full advantage of its powerful features. several features which ensure accurate When you open a new issue, you open and reliable placement of text and graph- a blank representation of the page you'll ics. One of these commands is "snap to TRAIN TODAY for an exciting money- making career in: be working with (it's called the "mini grid," which automatically causes items Electronics Engineering Technology Computer Programming Data Processing page "), and a blank article window to the to snap to the closest left -hand margin. Information Systems Drafting with C.A.D. Text can be directly into the Another handy tool for aligning arti- NATIONAL EDUCATION CENTERS has 50 compuses left. entered nationwide, so there's a Center near you. In as little as article window from MacPublisher's cles is "snap to guides." With this com- 9 months, you can train for a high -tech career, in a state -of- the -art environment. word processor (albeit, a cumbersome mand, you set the distance (in either ASK ABOUT OUR BENEFITS! Day and Evening classes, Financial Aid to those who qualify, and Job Place- task) or from Microsoft Word or Mac - inches, points /picas or cm) that the text ment Assistance! Many of our schools are Approved files. A telecommunications pro- or graphics will appear from the top mar- for Veterans Training, and all are accredited mem- Write bers of either N.A.11..S. or AI.C.S. gram also is provided (NewsWire DA) gin and left hand margin of the page. SO DON'T DELAY! For information send in the handy coupon today. Or call 7 days a week - for sending and receiving text files. A A third way to make accurate layouts TOLL FREE: I National separate allows you to transmit is by calling up an item's specification program I Education pictures which are sent in Xmodem for- sheet once you've laid it out on the page. Centers The spec sheet covers everything from mm I=in see al=B>aBf =B> =me. mat, the standard for binary files. r-Nattonal Education Centers - Headquarters Existing issues open to a dummy page, the distance the article is located from the 1732 Reynolds Irvine, CA 92714 'The program I am interested in is:._ _._.. which features solid blocks of text and top and side margins (called "x" across Year of High School Graduation or G.E.D. graphics. Each block displays informa- and "y" down, respectively), as well as I NAME: about the element it represents such leading (space between lines), kerning ADDRESS: tion I CITY/STATE /ZIP (space between characters) and various as the name of text blocks, number of PHONE: ME -387 ' lines, number of characters, and carry- shades of gray that can be used. The spec over articles (if any). Picture blocks are sheet also allows you to change type presented in white. styles, type faces or even substitute arti- Other symbols Mac users will recog- cles, if desired. (This later feature is han- COIMPUCOUEB® nize include the familiar Apple icon for dy for laying out columns that repeat in a desk accessories, a file menu, edit menu, publication each issue. The new copy format menu, font, style and size menu. simply replaces the old in seconds.) Two new menus are layout and print. Two other ways to adjust layouts are To create a new issue, you must choose either through the program's maxi page the type of printer you're using (Image - command, or with depth justification. writer I /II, Laserwriter, etc.), name the Maxi page provides a full screen view of issue, and then set page margins, thé exactly what the page looks like. I gener- number of grid columns and the spacing ally perform all initial layouts in mini between columns. page and then switch to maxi page for Page margins can be set in inches, last-minute adjustments. With depth jus- picas /points or centimeters. For added tification, text can be made to fit in a spe- COVER YOUR INVESTMENT precision in layout, the page can be divid- cific vertical space (the leading is adjust- Macintosh Monitor & Keyboard 12.95 ed into as many as 48 equal columns (or ed so that the text fits perfectly). Macintosh Plus Keyboard add -1.00 grids). 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www.americanradiohistory.com SOFTWARE FOCUS...

tide and it can appear in a different font, files. To use a MacPaint or MacDraw im- rules, etc., without having to measure or style and size than the copy that preceded age, you must convert the file to a "Mac- copy the image to the camera. it in the previous carryover. Publisher picture." Luckily, this is a sim- Although articles can be carried over ple matter which is done as soon as you manually, one of MacPublisher's most try to load the graphic to the clipboard. The Acid Test A copy must be made each graphic powerful features is auto flow text. Using of Is it possible to use a desktop publishing this command, when an article has been before it can be used in the program. program such as MacPublisher II to pro- clipped into carryovers, any newly-added Then, with your copy of the original art- duce a professional -quality newsletter? or deleted text will push the other carry- work, you must make a second copy to To take it through the paces, I recreated a over text either forward or backward. the software's clipboard. page from the September, 1986 issue of Another powerful feature is auto re-lay - Once the clipboard copy is made, the Modern Electronics. be called up out, which causes changes made in article camera can from the edit The text was entered in and typeset us- or picture windows to be made to the lay- menu. The camera actually is a transpar- ing MacPublisher II's word processor out pages automatically. Both features ent grid which fits directly over the clip- and outputted on an Apple Imagewriter are user -selectable, rather than defaulted board image. To make a camera photo, printer. Graphics were created using (like Pagemaker). simply click on the image. A mini camera MacPaint. For precise layouts, several different "flashes" and you are instructed to name As you can see from the accompanying new rulers can be accessed. The desktop ruler your MacPublisher photo. illustration, it is possible to create a pro- measures depth, and can be placed any- Artwork can be cropped once it has fessional- looking page from MacPub- laid box. To where in the layout. To use it, simply been out by using the sizer lisher II. This example took me about 90 click on the ruler to see how many inches restore the dimensions of the artwork, minutes to typeset, keyline and create the from the top you have available for copy you must hold down the shift key while original artwork. or graphics. The window ruler can then adjusting the sizer. For a more professional appearance, be used to measure the copy or graphics While the above method is adequate the article could have been typeset on an so that an exact block is laid out. for making minor adjustments, a far bet- Apple Laserwriter, which provides 300 is by using the With these powerful tools available, it ter way to crop photos dpi (dots per inch) resolution. While a is relatively simple to wrap text around desktop and window rulers in the camera Laserwriter doesn't come cheap, the The photos, or match copy to a specific size. before snapping your image. camera good news is that many laser typesetting For those of us who don't want to mea- can be cropped to conform to full page, services are available that will typeset a sure every block of text, MacPublisher II half -page, third -page, '/ -page, 2/3 -page page for approximately $10. Many "in- even can lay out text automatically. To and 1/4-page sizes, or adjusted to what- stant print" shops also offer this capabil- take advantage of this feature, simply use ever desired width and depth by either us- ity. As a result, it's not necessary to in- the "scissors" to lay out an article on the ing the sizer box or calling up the specifi- vest thousands of dollars in printing mini or maxi page. If the article extends cations sheet. equipment to produce a professional - below the bottom margin of the page or Creating original images with the quality piece. "snap to guide" setting, a dialog box will graphics palette takes a little getting used ask you whether the text should be laid to. The palette allows you to create hori- out as is, clipped to fit, or canceled (with zontal and vertical ruled lines, rectangles Conclusion a clipline inserted into the original article (with either square or rounded corners) so that a precise layout can be made). An- and circles. Every graphic created is a To sum up my experiences with this soft- other way to adjust layouts is to activate combination of three pen lines which can ware package, MacPublisher II is a pow- auto flow text and use the sizer box to ad- be of any thickness and have any of 99 erful, professional -quality page make -up just text blocks either up or down. different patterns. Rectangles and circles program that is well thought -out and also can be filled with a fourth pattern. moderately easy to use. While its capabil- Graphics Are Cumbersome Although the palette isn't difficult to ities may exceed the needs of many of us, work, I found the procedure for keying for those who are professional writers or In contrast to the ease in which text can rules and boxes a bit awkward. Unfor- who have the need to create professional - be laid out on a page, creating and using tunately, for each rule that's placed on a quality newsletters, brochures, books, graphics with MacPublisher II is a bit page, a separate new file needs to be etc., it offers tremendous value for the more tedious. created. It's too bad that the program money. Graphics can be created from Mac- wasn't designed with a graphics palette (Available from Boston Software Pub- Publisher II's graphics palette or brought similar to Pagemaker's, which allows lishers Inc., 1260 Boylston Street, Bos- in from existing MacPaint or MacDraw you to directly create squares, circles, ton, MA 02215.)

66 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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www.americanradiohistory.com Ululi EL ECTR ONIC S NOTEBOOK/II/ItIME Keychain Electronic Projects

Forrest M. Mims III t3V NOTES The transistorized "pocket" radios of a few years ago were usually much too 1. R1 co,JrROLS bulky for a shirt pocket. The most re- SENSITIVLT Y. OK markable physical feature of today's USE shirt pocket electronic devices is that they TO FIXED really do fit in a shirt pocket. In fact, sev- RESISTOR (~Look). eral ultra -thin credit card -sized radios and calculators can be easily slipped into 2. RUN TRACES the same pocket. To PIrJS 6, 8 The frontal dimensions of today's AND 10 uNDER pocket electronic devices are not surpris- LM CO NtiE CT ing. But their amazing thinness is an impressive technological achievement. In TO Q1 VIA SUMPER. fact, it is so impressive that until six months ago I was convinced that it was impossible for individual electronics ex- 3. RESISTOR CODE: perimenters and engineers to duplicate 3°os1 = 3I this feat by hand. L K = 102 Fortunately, this gloomy outlook has Loe K = LOH been completely reversed now that miniature surface -mountable components (SMCs) are becoming more widely available. Working with SMCs requires new assembly techniques and careful atten- Q1 PNOTOTRAr.ISISTOR (`rETTNEF: CR10TE-1 tion to detail. Nevertheless, I have found oR sit`ItLAR) that finished circuits made with SMCs can often be assembled more rapidly Fig. 1. Light meter with LED bargraph display. than conventional circuits using traditional components with leads. Moreover, the tiny size of SMCs and the fact they known to electronics prototypers, was a cently, I discovered some plastic identifi- can be attached to both sides of a circuit pioneer in bringing such kits to market. cation tag holders with attached key board (with either solder or conductive The previous two issues of Modern chains. Those tag holders are made of adhesive) provides unprecedented design Electronics featured a two -part article sturdy plastic and have a 2- millimeter flexibility. Thanks to surface -mount describing surface -mount technology. opening for insertion of a small identifi- technology, it is now possible for experi- This article, which replaced this column, cation card. They appeared to be just the menters and small companies to again included details about surface- mount- right size for housing miniature sur- take the lead in designing and building able components and soldering methods. face -mount projects, so I bought several. creative personal electronic devices. Also included were construction details The keychains are distributed on a Though circuits made with SMCs are for three miniature circuits made with wholesale -only basis by the W.T. Rogers surprisingly easy to design and assemble, SMCs. (Back issues are available for Company (Item No. 1132) and retail for finding surface -mountable components $2.50 each.) around 70t each. I purchased mine from can be difficult. But this situation is be- The remainder of this column is devot- the Paul Anderson Company, a large of- ginning to change. For example, the ed to three additional circuits whose min- fice supplier in San Antonio, Texas. Mouser Electronics catalog lists a variety iature size is made possible by SMCs. Figure 1 is the schematic of the first cir- of surface -mountable resistors, capaci- Even if you don't now care to assemble cuit I installed in one of those tag hold- tors, ICs and LEDs. If you live in or near one of these circuits, you will gain a bet- ers. This circuit can be used to indicate a major city, you can purchase SMCs ter appreciation of surface -mount tech- voltage and resistance by omitting photo - from electronics distributors that repre- nology by reviewing the details of their transistor Ql. With Ql in place, the cir- sent SMC manufacturers. At last fall's construction. cuit becomes a rudimentary light meter. giant WESCON electronics trade show, I When QI is dark, all the output LEDs found a dozen or so companies that sell Keychain Light Meter glow. Conversely, when QI is saturated assortments of surface -mountable parts. with light, none of the output LEDs Vector Electronic Company, a firm well While visiting an office -supply store re- glow. Intermediate levels of light cause

68 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics www.americanradiohistory.com varying numbers of LEDs to glow in bar - graph fashion. Known as a parallel or flash analog -to- digital converter, the Fig. 1 circuit consists of a parallel array of comparators, each of which is connected to a reference voltage provided by a tapped voltage divider. Resistors RI through R5 form the voltage divider. The LM339 contains four comparators on a single chip and is an ideal choice for this circuit. The output of each comparator directly drives one of LED2 through LEDS through current- limiting resistors R6 through R9. Power -on is indicated by LED1. Figure 2 will help you better appreciate the significance of surface -mount technology. This is a photo of the Fig. 1 circuit (less QI) assembled with conventional through -hole components. (Its construction was described in Integrated Cir- cuit Projects, Volume 4, a book I wrote for Radio Shack in 1975.) At 0.45 cubic inch, the keychain version of the circuit Fig. 2. LED bargraph assembled using conventional components. occupies less than half the volume of the 9 -volt battery (1.1 cubic inches) that powers the conventional version of the of the board with a protective layer of Wire the board by first positioning the Fig. 2 circuit. tape and etched away all unwanted cop- LM339 in place and securing it flat Figure 3 shows the etched circuit board per. Total preparation time was around against the board with a piece of masking I made for the keychain light meter. The 45 minutes. tape across one end of the chip. This 0.5 -mil thick board is double -sided and Caution: Always follow the manufac- done, touch the pointed tip of a I5 -watt can be easily cut to size with scissors. A turer's recommendations regarding safe- soldering iron to a corner pin and apply 12 " x 18 " sheet of this board is available ty and disposal when using circuit board just a tiny bit of solder. Because of the for $2.50 from Edmund Scientific (Cat. etchant products. Remember that et- pretinning of the board's copper traces No. #R35,652). chants will permanently stain clothing and the plating on the IC pin, the connec- Only one side of the board is used for and painted surfaces and corrode metal. tion will be instantly made. When a se- the light -meter circuit. However, sur- Incidentally, notice that the board in cure connection has been made, carefully face- mountable components can be sol- the upper photo in Fig. 3 shows three remove the tape and make sure the re- dered to both sides of a double -sided solder bumps strategically located maining pins are still aligned. If they are, board if provisions are made for making around the perimeter of the coin cell. solder the opposite corner pin. Then sol- interconnections between the two sides. These are simply three small copper lands der all remaining pins. Use very little sol- As for the board's layout pattern, designed to receive solder bumpers that der in all cases. there isn't one. Instead, I sketched an ap- secure the coil cell in place when the Chip resistors and LEDs can also be proximate layout on a notepad. Then I board is slipped into the ID tag holder. soldered into place with the help of mask- cut the board to size and polished it with After the board is etched, all compo- ing tape. Simply attach a chip component steel wool. Next, I placed the various nent footprints must be plated with either to the board with a small piece of tape components, including a 2016 lithium solder or tin to permit soldering. TIN - across one end of the chip. Solder the ex- coin cell, on the board and marked their NITTM tin plating chemical is available posed end as described above. If neces- terminal or pin locations with a pencil. from The Datak Corp. Or standard rosin sary, gently press the end of the chip into After removing the components, I pen- core solder can be flowed onto the the solder with a pencil eraser or other ciled in the desired traces. Pins of the board's copper traces. It is important to implement to make sure it is flat against LM339 that were to be interconnected avoid applying excess solder. After plat- the board. Remove the tape and solder were interlinked under the chip. After ing the board, use desoldering braid to the remaining end to the board. Do not tracing the penciled traces with a fine remove any excess solder. For best re- try to press the second end of any chip point resist pen (Radio Shack Cat. No. sults, the solder layer should be very thin component downward since the other 276 -1530A or similar), I covered the back and as flat as possible. end is already soldered rigidly in place.

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 71 www.americanradiohistory.com ELECTRONICS NOTEBOOK...

This is one reason why it's important that the solder plating over the component footprints be very thin and flat. Use as little solder as possible when attaching the SMCs. In fact, you may be able to use no solder at all if the solder coating you applied to the footprints is very flat and uniform. In this case you might be able to reflow the solder over the pins or around their terminals by simply pressing them against their footprints with the tip of the iron. Should you accidentally bridge two or more traces with solder, immediately remove the bridge with desoldering braid. Figure 4 shows the completed keychain - 1.95' light meter (lower photo). Note that only one jumper lead was required (from pin 6 of the LM339 to QI). Though I planned to use a surface -mountable trimmer resistor for R1, I later substituted a fixed 100,000 -ohm resistor. Before building this circuit, I spent a good deal of time wondering how to make a switch that would fit into the 2- millimeter space inside the keychain tag holder. Though I tried several ap- proaches, the simplest proved to be the best. The switch is simply the L- shaped piece of 5 -mil unetched pc board shown in Fig. 3 covering part of the coin cell. Both sides of the L are covered with transparent tape, which is trimmed to match the outline of the L. A narrow strip of tape is removed from the coin cell side of the end of the L that covers the cell. One end of a short length of wrapping wire is soldered to the opposite end of the L. The other end of this wire is soldered to the negative supply trace on the circuit board. The switch is completed by securing it to the end of the board with a short piece of transparent tape that functions as a hinge. Test the circuit by placing a coin cell, Fig. 3. Etched pc board for lightmeter circuit (upper) and hand-wired board using sur- positive terminal down, between the face- mountable components (lower). switch and the board. When the exposed copper along the underside of the end of the L is pressed against the negative side LEDI fails to glow, you will have to re- slot that simplifies removing the board. of the cell, LEDI should light. As QI is move a slightly wider strip of tape from Insert the end of a small screwdriver or darkened, LED2 through LEDS should the end of the switch L. If LEDI glows similar implement into this slot and gent- turn on in sequence. when the case is not squeezed, you must ly push the board out the opposite end If the board passes its operating test, bend the end of the L upward slightly be- until you can grasp it. Then pull the insert it into the tag holder. If all goes fore reinserting the board in the case. board from the case. well, LEDI will light when the power cell The end of the tag holder opposite the Chip resistors and the SO (small out- end of the tag holder is squeezed. If keychain holes has a small opening or line) version of the LM339 used in this

72 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

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circuit can be obtained from Mouser a very low level of light reaches Ql, the LICENSED Electronics and many other sources. The ring begins to rotate more rapidly. Rota- ELECTRONIC TECHNICIAN! LEDs are Mouser Electronics No. tion rate continues to increase until the ME351 -2711 chip devices or equivalents. light level becomes so high that Ql is sat- Phototransistor QI is a Stettner Elec- urated and the 555 oscillator is disabled. Earn up to tronics No. CR10 TE -1. Before building a surface -mount ver- $30 an hour sion of this circuit, assemble a test ver- and more! sion using conventional components and Keychain Light Level Indicator Learn at home in spare time. a solderless breadboard. This will allow No previous experience needed! The keychain light meter described above you to select an appropriate value for Cl indicates the light level with a bargraph that gives an optimum rotation rate for No costly school. No commuting to class. readout. The circuit shown in Fig. 4 is the light levels you want to monitor. The Original Home -Study course prepares you for the "FCC Commercial Radio- less precise but more fun to build and Figure 5 shows the completed keychain telephone License ". This valuable license use. It indicates the intensity of light by light sensor with rotating ring readout. is your "ticket" to thousands of exciting means of a ring of 10 LEDs that appears The board for this circuit is laid out in the jobs in Communications. Radio-TV, Micro- wave. to rotate. The light intensity controls the same fashion as that for the Fig. 1 circuit. Computers, Radar. Avonics and more! You don't need a college degree to apparent rotation speed. The chief difference is more jumpers that qualify. but you do need an FCC License. A 555 oscillator and a 4017 counter/ are used. Compare the circuit diagram in No Need to Quit Your Job or Go To School decoder are the main elements of this cir- Fig. 4 with the completed circuit in Fig. 5 This proven course is easy, fast and low cuit. In operation, the 555 generates an and you can see that jumpers are used to cost! GUARANTEED PASS - You get your FCC License or money refunded. Send for oscillating signal whose is deter- connect rate LEDO through LED4 to the re- FREE facts now. MAIL COUPON TODAY! mined by the light level at Ql. For each spective pins of the 4017. pulse from the 555, the 4017 advances A do- it- yourself squeeze switch identi- commanu PRODUCTIOns FCC LICENSE TRAINING, Dept 220 one step. When QI is dark, the LEDs cal to the one used in the Fig. 1 circuit is P.O. Box 2223, San Francisco, CA 94126 switch on in a slow sequence and the used for this new circuit. The SO version Please rush FREE details immediately! wheel "rotates" very slowly. When even of the 4017 and all resistors and capaci- NAME ADDRESS CITY STATE ZIP J Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 73

www.americanradiohistory.com ELECTRONICS NOTEBOOK...

tors can be purchased from Mouser Elec- tronics and many other sources. The SO 555, preferably the CMOS or low-power version, is available from Signetics, Exar and the SMDTM Technology Center. Transistor QI is available from Stettner LED Electronics. DISPLAY Ultraminiature LED Pulse Transmitter Regular readers of this column and my books may recognize the circuit at the left in Fig. 6 as one of my favorite LED pulse i.1 drivers. This simple circuit can drive an LED with a series of hefty pulses having an amplitude of hundreds of milliam- RL peres and a duration of around 20 micro- seconds. Though I have built many versions of this circuit, some quite small, availability <<,IN SQUEEZE of surface -mount components has al- s'as Ci tiC17 c ELL lowed me to assemble the tiniest version yet. At the right in Fig. 6 is shown a photo 2 of the result. The complete infrared pulse Fig. S. Wired transmitter (less battery) measures only miniature SMT light sensor with rotating ring display. 8 mm x 9 mm and is just slightly over a millimeter thin. In other words, the en- sions, I did not trim the board to size un- nects the positive supply lead (lower lead tire circuit is smaller than the nail on your til it was completed. In the meantime, it extending from board at right in Fig. 6) little finger. remained as a corner on a postage- stamp- with the emitter terminal of Ql. I laid out the board for this circuit in size board. Resistors R1 and R2 and capacitor Cl the same manner as those described Notice that the completed circuit in- are available from Mouser Electronics. above. But because of its tiny dimen- cludes a jumper wire. The jumper con- The infrared LED is a Stettner Electron-

Qz Q1 + To+r.V

L TUMPER

2ZK LED RL

½inmi Fig. 6. A LED pulse transmitter (left) and SMT version of the circuit with scale (right).

74 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com special- the circuits described above I have as- ADDRESSES tools will also work. Of course, ized tools and equipment can simplify the sembled a new family of miniature sur- Datak Corp. assembly of surface -mount circuits. But face -mount projects without using a sol- 3117 Patterson Plank Rd. not having access to such equipment dering iron. These new circuits illustrate North Bergen, NJ 07047 doesn't prohibit access to the surface - more of the exciting possibilities that 201 -863 -7667 mount age. await those who join the surface -mount Edmund Scientific Co. I hope you are by now as excited as I technology age. Since I think you will 101 E. Gloucester Pike am by the prospects opened up by sur- find them rather interesting, I'll describe Barrington, NJ 08007 face -mount technology. Since building them in a future column. 609-573 -6250 Mouser Electronics 2401 Highway 287 North Mansfield, TX 76063 817- 483 -4422 SMD Technology Center Our 5855 North Glen Park Rd. Milwaukee, WI 53209 catalog 414- 228 -7632 Stettner Electronics, Inc. will make 3344 Schierhorn Court Franklin Park, IL 60131 work MCM 800- 251 -4558 (toll free) your Vector Electronic Co. EIECaONICs 12460 Gladstone Ave. easier! P.O. Box 4336 Sylmar, CA 91342 818 -365 -9661 Catalog '14 from MCM has all the things you're looking for in a great electronic parts catalog. Our wide selection will save you time! ics No. CR10 IR. The SOT -23 transistors An unbeatable line -up of parts and are available from many sources; the products will make us your one and ones I used were purchased in 50-unit only source. You'll always find the things you need when you need reels from the Surface Mount Technol- them! ogy Center. Save money, too! Great, low prices help you get more value for the Going Further money you spend. Enjoy the fast, dependable service that has become our Each of the miniature circuits described trademark. Your order will always be correct and delivered here was built in less than three hours. on time - that's guaranteed! That's certainly comparable with the Convenient ordering - our toll-free numbers put us just a phone call away! to assemble much larger time required Call TODAY for the latest edition of the MCM catalog. Discover how this great versions of the same circuits using con- book will make your work easier! ventional components. The only tools I used were an inexpensive handheld soldering iron, desoldering braid, tweezers Catalog 414 Now Available and a magnifying loupe. In other words, surface-mount technology is well within Call TOLL -FREE 1- 800 -543 -4330 the grasp and budget of most experimenters. In Ohio call 1- 800 -762 -4315 This came as quite a surprise to some In Alaska or Hawaii 1- 800 -858 -1849 of the surface -mount experts who examined these circuits at last fall's WES- CON. Most of these engineers are so in- MCM ELECTRONICS volved with highly sophisticated sur- 858 E. CONGRESS PARK DR. face -mount soldering methods that they CENTERVILLE, OH 45459 A PREMIER Company have overlooked the fact that simple CIRCLE 50 ON FREE INFORMATION CARD ME-21

Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 75

www.americanradiohistory.com 1

Troubleshooting, Servicing and Theory circuits used in AM and FM receivers, in- tronics educational tool that uses proj- of AM, FM & FM Stereo Receivers, 2nd cluding both vacuum -tube and solid - ects to build as the "hook." So whether Edition, By Clarence R. Green & Robert state designs right on up to sophisticated you build all of them (more than 25 proj- M. Bourque. (Prentice -Hall. Hard cov- PLL synthesized tuning and digital pro- ects with complete plans) or not, you'll er. 556 pages. $29.95.) cessing schemes. learn how the circuits and devices work. This is as much a textbook that empha- All in all, this book should provide a Among the many construction proj- sizes the theory of AM, FM and FM- good foundation for a career in servicing ects included are a light controller to stereo receivers as it is a traditional trou- AM and FM receivers. Its general elec- smoothly dim or brighten lamps, a digital bleshooting manual. Taken in this vein, tronics section is a bonus that can serve as humidity control, an automobile bar - it can easily be used as the textbook in a a basis for further preparation for other graph tachometer, a testbench audio am- classroom course on broadcast AM and areas of servicing. plifier, anti -theft car alarm installation, FM theory whose ultimate aim is not to The Second Book of Modern Electronics an electronic security alarm control cen- show the reader how to design this type Fun Projects. Edited by Art Salsberg. ter, a device to substitute up to 200 select- of equipment, but to prepare him for ef- (Howard W. Sams. Soft cover. 81/2" x able musical tunes for your standard tele- ficient troubleshooting. It even has end - 11 ". 183 pages. $12.95.) phone ringer, an interface device to ex- of- chapter summaries and questions This Second Book of ... provides even plore electronic music with a Commo-

(with selected solutions at the back of the more projects than the First Book of . . . dore C -64 computer, and a host of test in- book). that was also recently published. Like its struments. The latter selection includes a General circuit fundamentals are dealt predecessor, it consists of detailed elec- high- frequency ac probe /voltmeter that with in the first eight chapters. Then tronics construction and design material can measure rms volts to beyond 10 comes the "troubleshooting" section in that's logically divided into eight sections MHz, an impedance bridge, a true -rms which tools, test equipment and basic to reflect the category they're in: Intro to adapter for a 3 1/2-digit DMM, a high -fre- procedures are introduced, followed in Electronic Projects, Home Electronics, quency dual -pulse generator, a 16 -bit subsequent chapters with analyses of and Audio /Video Electronics, Security Elec- logic analyzer, and precision voltage troubleshooting procedures for specific tronics, Telephone Electronics, Compu- sources. The concluding section on elec- pieces of AM and FM equipment. Within ters, Test Equipment and Electronic tronic designing illustrates how to think the troubleshooting section is more the- Designing. out creating of digital circuits to culmi- ory that focuses in detail on the specialty It, too, serves as a wide- ranging elec- nate in a car -theft alarm and an EPROM

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CIRCLE 44 ON FREE INFORMATION CARD 76 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com FREE! New Catalog of tester, as well as devising programmable specifications, device orientation and Hard -To -Find timebase/dividers. quantities of parts per reel are given. Ap- The projects are based on material that plications data includes mounting, sol- Precision Tools appeared in Modern Electronics maga- dering and board -cleaning recommenda- zine, with authors upgrading and refin- tions, and standard layouts. For a copy ing their work. From easy -to -build to of "Surface -Mount Components" (No. more complex ones, they'll provide read- ASP- 600A), write to: Sprague Electric ers and doers with many, many evenings Co., Technical Literature Service, P.O. and weekends of building fun and learn- Box 9102, Mansfield, MA 02048. ing. Moreover, you'll be able to have Resistor Networks Guide. 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www.americanradiohistory.com X11111 PC PA PERSI//Il

Two Hybrids: Tandy 3000 HL, Words & Figures

By Eric Grevstad

Maybe it's just that I don't like Las Vegas -everybody says it was a great show and a sign that the industry slump is over, but my favorite part of last November's Comdex /Fall was a visit to Hoover Dam. Probably I was put off by the sameness of it all; 100 hard -disk menu managers, so many under -$1,000 PC clones that I might have been at the Kitchen Appli- ance Expo, and, of course, desktop publishing, desktop publishing, desktop publishing ... . Still there were attractive trends. Data - vue and NEC showed laptop portables with readable screens, 3.5 -inch disks, and double (9.54 -MHz) PC speed; NEC's MultiSpeed costs $1,995 with 1111111i 640K, two drives, and 512K of SideKick- style ROMware, while Datavue's Spark will be a tempting $995 with 384K and one disk, though you'll want to add more RAM, a second drive, and maybe a back- lit screen and a modem. Crowds sur- A fast runner without a huge footprint: Tandy's 3000 HL. rounded IBM's PC Convertible, chant- ing "Woof, woof, arf, bow, wow." And the 80386 chip is on the way, not dy's made probably its best shot yet at 640K instead of 512K on the mother- waiting for an IBM standard or DOS 5.0. corporate desks: the trim -sized 3000 HL. board sockets. Compaq's Deskpro 386 found its way in- Compared to the regular 3000, Tan- On the other hand, while the cost of to a number of booths, software vendors dy's bulkier AT clone, the HL has three Tandy's 40- megabyte hard disk is breath- trying to make buyers think their pro- fewer slots (three 8 -bit and four 16 -bit), taking ($2,199 with controller), so is its grams always run that fast, and 386 desk- comes with a 360K instead of 1.2M flop- performance. I'd earlier scoffed at hot - tops and add -on boards were every- py drive (hooray!), can't expand past rodders who say, "Oh, 30 instead of 90 where. In fact, there's a growing impres- four megabytes of RAM, and can't run milliseconds access time makes a big dif- sion that 80286 micros like the AT will be multi -user terminals under Xenix. As a ference." It does. Tandy's 40MB drive, a bypassed, serving mostly as speedy XT single -user station, though, the HL of- Control Data Wren model, is a screamer. equivalents while the future's multitask- fers good looks, a snappy AT -style key- Between the hard disk and the 80286, going software belongs to the 386. That's board, and the speed of an 8 -MHz AT. It ing back to my old 1200 HD is no fun. not necessarily a bad fate, judging from raced through BASIC benchmarks and Unless you're zealous for Xenix, or hold- the crop of hybrid XT -AT machines late- Lotus sessions four times as fast as my ing out for even more speed and eventual ly. I've been testing just such a machine, XT clone, and the only software incom- multitasking with the 386, the 3000 HL is using a program that's a hybrid of Lotus patibility I found was that the disk kept really a prize. 1 -2 -3 and a word processor. spinning while I played Ms. Pac -Man. The price is right: $1,699 for the HL 1 -2 -3 Meets system with one drive, parallel port, and A,B, C Speed & the Single User clock. Smart shoppers know, however, Lotus 1 -2 -3 Release 2 has seized control that Tandy's excellent prices for CPUs since I described Release lA as the Clas- The idea of an "ATjr," an XT- compat- mask medium to steep tags for peripher- sic Coke of the spreadsheet world (June ible system with the AT's swift 80286, als -MS -DOS 3.2 is a shameful $99.95 1986), but the lA compatibles and en- isn't new. I think the ITT Xtra XP was extra; the several video cards offered are hancements keep coming. The newest, the first; IBM sells an obsolete -parts all named "Deluxe," but you can do bet- Lifetree Software's Words & Figures, clearinghouse called the XT -286, with an ter for less with third -party items; and strikes me as the best Lotus clone yet - old 6-MHz CPU and a case that won't Tandy, which buys RAM chips the way and a ferocious argument against paying hold AT -size expansion cards. Now Tan- Ford buys rivets, was too chintzy to put $495 for the original.

78 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com Like other clones, W &F is affordable to type one in your document). You can display, but you'll miss features such as ($195), not copy -protected, and ready to flip between spreadsheet and text any- undelete, a delete word command as op- read existing .WKS files, macros, and time with Alt -F10, and the same window posed to a block operation, or support templates or produce new ones. The command that lets you see two parts of a for multiple margins or spacing within a screen display, slash commands, and sep- spreadsheet can split the screen between a document. arate graph -printing program are in- spreadsheet and document. Nevertheless, if you want a first -rate stantly familiar, with a few differences, Not bad, you say; I'll bet there's a cut - spreadsheet that you won't have to leave such as pop -up menus instead of hori- and -paste procedure to copy spreadsheet to write a letter or memo, Words & Fig- zontal listings of files and ranges; where rows into text. No, there's a variation on ures works wonderfully. If you disagree, commands are slightly different, W &F the "insert lines" command that inserts a there's a 60 -day money -back guarantee. adjusts when reading old macros. live worksheet window into your docu- Seeing companies like Lifetree, I think There are worksheet enhancements, ment, a frame behind which you scroll "Lotus" stands for List -price vendor some familiar in Release 2 and some orig- material vertically or horizontally and Opposed To Unprotection and Site li- inal: math coprocessor support, efficient within which you have a working spread- censing. kf memory management and expanded sheet cursor with spreadsheet commands memory use up to 9,999 rows by 256 col- and recalculation. Changes appear in Names and Addresses umns, the ability to hide cells or trans- both the spreadsheet, which you can save Tandy Corp./Radio Shack pose a range from row to column (or separately as a .WKS file, and the com- 1800 One Tandy Center vice -versa), three instead of two database bined document (.WAK) file. Fort Worth, TX 76102 in- You can make a .WAF file containing sort keys, and an "audit" mode that Lifetree Software Inc. which cells hold values, just text with no spreadsheet excerpts, stantly shows 411 Pacific Street er- though the word processor is the mildly formulas, and circular references or Monterey, CA 93940 W &F is as fast disappointing part of a superb integrated rors. Unlike many clones, 408- 373 -4718 as 1 -2 -3 and sometimes faster -on my program. Lifetree is careful to distin- 8088 system, it did a 1,000 -cell recalcula- guish W &F from its popular Volkswriter tions in 18 seconds compared to the 26.5 line, calling it a word processor for users seconds for Release #2. whose primary work is spreadsheets - By the way, there's one feature here the package calls W &F "The spreadsheet that Lotus lacks: The IT (Text) com- that lets you write about your numbers." mand turns W &F into a genuine word The editor's automatic reformatting is processor, controlled by similar slash quick, and I admire its handling of head- commands (you press the slash key twice ers and footers and PFS -style page break

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CIRCLE 35 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 79

www.americanradiohistory.com FOX EDITORIAL (from page 4)

MICROFOX Let's face it, playback -only equipment tell 'em that you're against anticopying Packed with features and perfor- is not as attractive to users as playback - circuits in home entertainment equip- mance, MicroFox redefines pocket- record equipment. Without a record ment. At the same time, why not com- size radar protection. This beautifully function on VCRs, recordings sold and plain about the outrageous charges from crafted superheterodyne unit is rented would doubtlessly be greatly re- the Bell Telephone companies since the scarcely larger than a deck of cards - duced since much fewer pieces of Justice Department forced them to split compactness made possible by a new equip- analog microchip, a Fox design exclu- ment would be bought. Just take a look up. This new freedom from a monopoly sive. Incorporating new ways to boost at the very low sales figures of video has resulted in us guys paying billions of sensitivity, MicroFox can actually ex- laser, disc equipment and recording sales dollars more every year to Bell (local tract weak radar signals buried in ran- to prove this, as well as the failure of phone rates have risen 30% to 40% in on- dom electronic noise. MicroFox em- ploys a varactor tuned microwave cav- RCA's playback -only video machine and ly a few years) yielding a greater profit to ity (VTC), the latest advance in non - accompanying recordings. VCRs, with the phone companies than even the radar signal reduction. When Micro - their recording capability, easily won out leading business corporations enjoyed Fox alarms, it has to be radar -not a here and, as a result of their high popu- this past year, while providing poorer false alarm. larity, are spitting out huge sums of service than ever to end users. uhsan$d41.0inOgshipping money from sales the very $299.95 8 software to people who, in their greed, could kill their golden egg. If you're as annoyed as I am about taking it on the chin as a consumer, why ad.-by don't you write your congressman and

(from page 5) 1- 800. 522.2636 For Orders Only LETTERS (617) 843.1900 For Information Cameo Enterprises, Inc. bers. A 2.2 -meg is "not available" ac- dio -TV distributors. Use a 2 -meg one if P.O. Box 63, Accord,MA 02018 you're having difficulty, which will work CIRCLE 40 ON FREE INFORMATION CARD cording to them also. The next step was to search the many fine and give you just a slightly reduced catalogs I have acquired. None had any range. The MM5837 IC is easily ob- Put Your Electronic listing of the IC and only one showed a tained, too. Digikey, one of our advertis- 2.2 -meg pot for which they wanted about ers, for example, lists it in its catalog for Skills to Work $8.00 and they do not do mail order. $3.13. There's no minimum purchase re- in ROBOTICS NOW! Now I ask you, where do I go from quirement here, either. A 2 -meg pot's BECOME A here? Even if I were to find a mail -order price ranges from 9W to $1.20 -Ed. source, they all have some minimum pur- ROBOT VEHICLE SMT Turn -On chase requirement, and I have no inten- Thanks for your article on SMT in ME PILOT/TECH tion of buying parts I don't need just to (Jan. '87). It's most timely since I'm try- get those that I do. Financial Aid 1 ing to squash a servo control down to pea Placement Assistance I believe that if you are going to pub- size for ultra mini R/C planes. Now lish articles of this type, you also have there's a light at the end of the tunnel some responsibility to either verify parts - you turned it on! availability or list a source that will sell As a small gesture of appreciation I en- the parts without forcing the purchase of close a one -year subscription to Modern unwanted parts. Electronics. It will enable me to follow I do think your magazine is among the Forrest Mims's SMT work. Once before HIGH PAY best of it's type. This complaint is not - about 20 years ago- another man piqued HIGH TECH unique to you but it has prevented me my sense of gratitude. I wrote to Lou EXCITING CAREERS from building a device which I had hoped Garner to thank him for his work in tran- would have helped my baby son sleep, sistor technology. Keep up the good work. Electronic, Hydraulic & which in turn would allow me to sleep! If Daniel A. Hoffman, II Robotic Skills Taught. you cannot suggest a source I must aban- Springfield, PA don this project. Call or Write for Lou Garner was the original "Solid Robert S. Heintz TODAY. State" columnist in Popular Electronics, FREE BROCHURE Dumont, NJ Ask About Our the latter now defunct. Forrest Mims was Correspondence Course his successor there and continues his re- (713)690 -0405 A 2.2 -meg potentiometer shouldn't be markable electronic experimenting in difficult to find, especially through ra- Modern Electronics. UNDERWATER VEHICLE TRAINING CENTER -Ed. 10046 Chickasaw, Houston, TX 77041

CIRCLE 41 ON FREE INFORMATION CARD 80 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com Hard Disk (from page 33)

to examine the plated media's tracks to with your hard -disk drive very thor- Chances are that you won't run into see if any unused ones were bad, but they oughly before you lay a hand on your any difficulties at all in adding a hard were all fine. So the shock mounting is computer. In some instances, you disk since the procedures are quite obviously good. might even have to remove a termin- simple and not time consuming. A Now to some test numbers. Average ating resistor, for example, which is typical charge for installing and for- access time measured 88 milliseconds, the case when adding OnBoard as a matting a hard -disk drive in the which compares to an IBM XT drive's 93 second hard drive in an IBM XT. Northeast section of the country is ms when using Core International's test Here, the resistor on the XT's drive $100, by the way. This is for a stan- disk. Rotational speed of the drive is a well its hard disk's standard 3,600 rpm, while has to be taken out, as as con- dard drive /controller (not a simple data transfer rate is also the standard 5 troller board. plug -in card) that's known to work megabits /second. Maynard states that Again, if you're adding a second with a particular computer. By doing OnBoard draws only 4.5 watts of power. hard -disk drive after you've already it yourself, you save money, gain a In all, this hard -disk card has a lot of formatted one that you've been us- sense of accomplishment and also things going for it. Its list is a bit pricey, ing, you'll have to reformat the first have fun. AE but the extra features and a name com- one so that the second one will be re- pany behind it makes it a bit easier to take cognized by the system. You can A Great Gift Idea. if dealer discounts are in order. avoid this only if you were installing -Art Salsberg both drives at the same time, which Send would allow you to configure the sys- =MODERN Conclusions tem for two hard disks when setting If you do any serious work with your up your first one. If adding one later, To A Friend. computer, as so many of you do, you'll have to copy all your exist- then you just have to upgrade to a ing files onto floppies and reload hard -disk drive, just as early IBM them later. (There's a way around PC owners moved to a higher disk - this through some trickery, though. operating system version, such as See PC Magazine, March 25, 1986, DOS 2.1 and now DOS 3.1 or 3.2. page 191.) Life is easier in the fast track. If you're adding an internal hard - There are certain caveats to look disk drive with a separate controller out for when buying a hard -disk kit. in an old model IBM PC, be sure to Be certain that the drive you buy can replace the computer's underpow- be booted up automatically as the de- ered switching power supply. Exact fault drive. Most can, but there are replacement types, 135 watts or 150 may not. watts, are cheap, and installation is a some that Your passport to ham radio adventure is If you're adding a hard disk as snap. Just remove a few screws, dis- TUNE -IN THE WORLD WITH HAM your second one, be aware of some connect a few cables, and slide the RADIO. Book tells what you need to Reverse the know in order to pass your Novice exam. possible challenges. For example, old supply out. proce- Cassette teaches the code quickly and should you decide to give up one of dure for installation of the new sup- easily. your full- height floppy -disk drives to ply. In real life, you'll have to loosen Enclosed is my check or money orderfor make room for an internal hard -disk a screw on a floppy drive frame to $10.00 of charge my ( ) VISA ( ) Mastercard ( ) Am. Express drive with separate controller, be move it forward to get enough room sure that you don't remove the one to move the supply a little forward Signature Acct. No that has a required terminating resis- past the case's lip. Also, the original Good from Expires tor pack on it (the other won't have supply's screw threads might be dif- Name one). So take out the drive that ferent than the substitute's, which doesn't have this device. On IBM may not come with screws to secure it Address PCs, this usually means that you to the chassis. So a fast trip to a hardware store may be in order. should remove the right -hand drive City State Zip (but check it out). Check this out before installing the Do read the instructions that come new supply. THE AMERICAN RADIO RELAY LEAGUE 225 MAIN ST. NEWINGTON. CT 06111

CIRCLE 47 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics 81

www.americanradiohistory.com Eprom Programmer (from page 46)

carefully smooth the stub tips with a fine file. Unlock the levers on SO1, SO2 and S03 on the Programmer. Lower DIS7 DIS6 the add -on assembly onto the main board, aligning the pins protruding JUMPER JUMPER from the bottom of the former with JUMPER JUMPER the ZIF sockets in the latter. Every- thing should line up squarely, and Ú there should be no need to force the C19 ? á JUMPER 2764 assembly into place. Set the levers on Ii the ZIF sockets on the Programmer to the lock position to secure the re- IC18 IC19

trofit board in place. 27128 Taking care to properly orient them, install IC18, IC19, DIS6 and JUMPER DIS7 in their respective sockets. Your -D14 K Programmer is now ready to program á and read large- capacity EPROMs.

JUMPER Checkout and Use C18 -JUMPER- You can check out the Stand -Alone EPROM Programmer's retrofit expansion module in the same manner - JUMPER - as you did for the basic unit, except

S06 LEVER w JUMPER

Fig. 11. Pc board wiring diagram.

that now you must use either 64K or and 32K EPROMs for which the 128K EPROMs and set switch S9 Programmer was originally de- accordingly. signed. Any time you wish to pro- With the addition of the expander gram, say, a 2716 or a 2732, simply module described here, you do not remove the retrofit board and you lose the ability to program the 16K are in business. AE

24 -Pin Wire Wrap Socket

Solder

Board (bottom) PC board Board (top) Lever 28 -Pin ZIF Socket

Fig. 12. Details for installing plug -in adapter socket pins that connect retrofit module to original EPROM Programmer's ZIF sockets.

CIRCLE 31 ON FREE INFORMATION CARD 82 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com MASTER THE NEW ELECTRONICS WITH McGRAW- HILL'S n po EI nics Series The fast, easy and low cost way to meet the challenges of today's electronic innovations. A unique learning series that's as innovative as the circuitry it explains, as fascinating as the experiments you build and explore.

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www.americanradiohistory.com Distribution Amplifier (from page 42) for marking their mounting hole lo- GAIN controls. By mounting the con- lug attached to the free end of the cations on the floor of the enclosure. trols in the holes drilled at these wire coming from the power -supply Drill holes large enough to accom- points, they will not interfere with board between the spacer and floor modate No. 6 machine screws for the the audio and video boards when the of the enclosure at one corner of the transformer and No. 4 machine project is assembled. power -supply board to ground it to screws for the circuit -board assem- Deburr all holes. Then use a dry - the chassis. blies at the marked locations. transfer lettering kit or a tape labeler Line the appropriate hole in the Next, cut the slots for the input to label the AUDIO GAIN and VIDEO rear panel with a rubber grommet. and output phono -jack assemblies in GAIN controls and AUDIO and VIDEO Then trim 3/8" of insulation from the enclosure's rear wall. The easiest INPUTS and OUTPUTS. If you use a both conductors at the free end of way to do this is with a nibbling tool. dry- transfer lettering kit, protect the the ac line cord. Tightly twist to- If you do not have such a tool, drill a labels by spraying two or three light gether the fine wires in both conduc- number of interconnected holes coats of clear acrylic over the front tors and sparingly tin with solder. around the perimeter of the slots and and rear panels. Wait for each coat Pass this end of the line cord through use a file to square up the slots. Drill to dry before spraying on the next. the rubber grommet into the enclo- the line -cord entry hole (make it Now mount all elements in place, sure and tie a knot about 4" from large enough for a small rubber starting with the power transformer. the prepared end inside the enclosure. grommet) and the bayonet -type fuse Before mounting the transformer, Mount the controls (and POWER holder, as shown in Fig. 8. (If you however, plug its secondary leads switch, if you have decided to in- prefer, you can mount an inexpen- into the T1 Secondary holes in the clude it) on the front panel in their re- sive chassis -mount fuse block inside power-supply board, solder into place spective holes and the fuse holder on the enclosure to the left of the power and trim the excess lead lengths. Use the rear panel (unless you have de- transformer and eliminate having to 4-40 x 3h " machine screws for mount- cided to use the internal fuse block). drill the large hole required for a bay- ing the circuit boards and 6-32 x '/, " Now, referring to both the schematic onet fuse holder.) or %" machine screws for the power diagrams and the wiring guides, in- Prepare the front panel as follows. transformer and rear -panel jack as- terconnect all elements as shown. First draw a light pencil line parallel semblies. Use 6 -32 or 4 -40 machine One conductor of the ac line cord to the bottom of the front panel 1 % " nuts and No. 6 or No. 4 lockwashers connects to one of the lugs on the to 1 " up. Then measure about 2 " in to secure all hardware, except screw fuse holder. Then one primary lead from both sides and strike short lines an insulated standoff post onto the of the power transformer connects to at these points across the first. These left screw end (viewed from the front one lug of the POWER switch, while a two points locate the centers of the of the enclosure) of the video jack as- length of hookup wire interconnects holes that must be drilled for the sembly. Sandwich the No. 6 solder the remaining lugs on both the POWER switch and fuse holder. When this has been done, wrap electrical tape over the contacts of the fuse holder and POWER switch's lugs to insulate the ac line from the rest of the circuit. Alternatively, you can slip over the whole rear portion of the fuse holder a 2" length of large - diameter heat -shrinkable tubing and shrink it into place to insulate this assembly. You have two choices for wiring the other line cord to the other primary lead of the power transformer. The simpler method is to twist together the remaining ac line cord conductor and remaining primary lead of the transformer and screw onto the connection a wire nut. The alternative is to slip a 1 " length of Fig. 8. Rear panel component mounting and wiring details. small- diameter heat -shrinkable tub-

86 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com ing over one wire, twist together and circuit. All measurements should be powered up, turning any knob clock- solder the wires and shrink the tub- made with reference to circuit wise should increase the gain, while ing tightly over the connection so ground (in this case, you can use the turning it counterclockwise should that it is fully insulated. metal chassis of the project's enclo- reduce the gain. If this is not the case Referring back to Fig. 6, wire the sure). On the power -supply board, with any given control, power down GAIN controls to their respective you should measure + 12 and - 12 the project and transpose the two boards, using the wires previously in- volts at the + lead of C3 and - lead outer wires going to it. stalled. Trim the wires to as short as of C4, respectively. You should also The normal operating position for needed before connecting and sol- measure + 12 and - 12 volts at pin 7 the GAIN controls should be straight dering them to the lugs of the controls. and 4, respectively, of IC/ on the up at the unity -gain setting. When- One lead of resistors R10, R11 and video board. Finally, you should ever the GAIN controls are used, al- R12 for the video circuit wires to the measure + 12 and -12 volts at pins 8 ways be sure to make a test recording signal (center or "hot ") lug of each and 4, respectively, of IC/ on the if one of the outputs is going to a of the VIDEO OUTPUT jacks. The audio board. VCR before making the actual re- other leads of these resistors tie to- If you do not obtain the proper in- cording. Check the test recording to gether to form a common junction dications, power down the circuit make sure no stages of the VCR are with the output wire from the video and correct the problem before pro- being overloaded. board. To make this connection, ceeding further. Start with the pow- You should now have the makings trim the resistor leads to length and er- supply board. If you obtain the of a fine -performing audio -visual wrap them around the post on the in- proper measurements, proceed to home entertainment system. AE sulated standoff. Trim the output the video board. If you get just the wire from the video board to length reverse of the correct measurements, before wrapping it, too, around the you cross -connected the power bus Order Back Issues of post and solder the connection. wiring; to correct this, simply trans- Connect and solder the free ends pose the two wires going to the video of the coaxial cables previously in- board. The same applies for the au- stalled on the audio and video boards dio board. If the voltages are re- State of the Art Kits by Hal -Tronix, Inc. to the appropriate lugs of the reversed on both the audio and the vi- VARIOUS CLOCK KITS HAL -5314 (Most Famous Clock Kit) . maining input and output connec- deo boards, it is easier to transpose 6 DIGIT ELECTRONIC CLOCK KIT. 12 OR 24 HOUR FORMAT COMPLETE KIT LESS POWER SUPPLY tors on the rear panel. Remember, the wiring at the power - supply board. ADAPTOR AND CASE RUNS OFF ANY 12 VOLT A C SOURCE REQUIRES 250 MA the center conductors of these cables Once you are satisfied that every- HAL -5375 (Alarm Clock Kit) $16.95 6 DIGIT ELECTRONIC CLOCK KIT 12 'OUR FORMAT go to the signal lugs of the jacks, the thing is working as it should, power ONLY OPERATE ON 12 VOLTS A C OR D C HAS TIME BASE ONBOARD COMES COMPLETE LESS POWER shields to the ground lugs. Finally, down the project and pull the line ADAPTOR AND CASE HAL -79 (Student Class Kit) $7.95 interconnect all ground lugs on both cord from the ac receptacle. Now 4 DIGIT BASIC ELECTRONIC KIT. WITH OPTIONS AND PROVISIONS TO MAKE IT AN ALARM CLOCK AND A ICs with the proper pre- D C OPERATED CLOCK COMPLETE LESS OPTIONS. jack assemblies, including the handling the POWER SUPPLY ADAPTOR AND CASE OPTION cl - TO MAKE IT AN ALARM CLOCK S2.95 ground lugs to which the coaxial ca- cautions for MOS devices, plug them OPTION #2 - TO MAKE IT A D.C. 12V CLOCK $495 CLOCK CASE - Reg. 56.50 Clock Case - When Bought with bles are connected. You can use bare into the sockets on the audio and vid- Clock Ka (ONLY) 54.50 12 VOLT A.C. ADAPTOR - Reg. $4.95 When Bought with solid wire to accomplish this, but eo boards. Make sure you install the Clock Kit (ONLY) $2.95 IC in each case, and make 60HZ TIME BASE Complete - $4.95 make certain that no portion of the proper CRYSTAL TIME BASE KIT USING MM5369 wire contacts the signal lugs of the sure that no pins fold under the ICs HAL NTSC RF MOD S19.95 BUILD YOUR OWN VIDEO RF MODULATOR A MINI T V TRANSMITTER FOR CHANNELS 3 OR 4 USING A SA W jacks. Obviously, it would be safer to or overhang their sockets. OUTPUT FILTER KEEPING CO- CHANNEL INTERFER- ENCE AT A MINIMUM COMES COMPLETE LESS CASE. use insulated hookup wire. Rotate the control shafts of the POWER SUPPLY AND HARDWARE NOTE CASE. POWER SUPPLY AND HARDWARE GAIN controls to determine where ENCLOSE S12 95 Extra HAL FG 100 569 .95 their midpoint settings are. Adjust FUNCTION GENERATOR KIT 1 HZ TO 100 KHZ IN FIVE Checkout and Use BANDS. AMPLITUDE AND OFFSET ADJUSTABLE OUT- each to its midpoint. Then carefully PUT IMP 500 OHMS WAVE FORMS - SINE. SQUARE AND TRIANGULAR ANDTTL CLOCKS TO 5V LEVEL 200 With the ICs still not installed in the and without disturbing the settings, NS RISE AND FALL TIME COMPLETE WITH CASE AND POWER SUPPLY AND ALL ELECTRNIC PARTS INCLUD- sockets on the audio and video push a pointer -type or other indicat- ING MANUAL SHIPPING INFORMATION: PLEASE INCLUDE 10% OF boards, plug the line cord of the Dis- ing knob onto each pot shaft so that ORDER FOR SHIPPING AND HANDLING CHARGES (MINIMUM 5250 MAXIMUM S10) CANADIAN ORDERS. Amplifier into an ac outlet the indicator is pointing straight up. ADD 57 50 IN US FUNDS MICHIGAN RESIDENTS ADD tribution 4% SALES TAX FOR FREE FLYER. SEND 22C STAMP and, if you included it, set the POW- This is the unity -gain position for OR SASE HAL -TRONIX, INC. co ER switch to ON. Use a voltmeter set each control. 12671 Dix- Toledo Hwy. G ti to 20 volts dc or so full -scale to check When the Audio /Video Distribu- P.O. Box 1101, Dept C. Southgate, MI 48195 for the presence of the proper volt- tion Amplifier is connected into your (313) 281-7773 Hours: 12:00 - 6:00 EST Mon: Sat ages at the appropriate points in the home -entertainment system and is 1111111. "HAL" HAROLD C. NOWLAND WBZXH

CIRCLE 43 ON FREE INFORMATION CARD Say You Saw It In Modern Electronics March 1987 / MODERN ELECTRONICS / 87

www.americanradiohistory.com MODERN ELECTRONICS MART

PICKS UP A WHISPER 50 FEET AWAY! Classified Commercial Rates: 90C per word, 15 -word minimum ($13.50) prepaid. (Word The model WAT -50 miniature FM tranmitter uses a count includes name and address, ZIP code and abbreviation each count as one word; 4 -stage circuit NOT to be confused with a simple wire- P.O. Box number and telephone number count as two words each.) Indicate free cate- less microphone. Simply snap the unit on top of a 9V battery and you can hear every sound in an entire house gory heading. A special heading is available for a $6 surcharge. First word only is set up to 1 mile away! Use with any FM radio. Tunes to any boldface caps at no charge. Add 20% for additional boldface words. frequency from 70mhz - 130mhz. Easy to assemble kit includes all parts and instructions. Only 29.98 tax incl. Mart Display Rates: 1 " x 1 col., $120; 2" x 1 col., $230; 3 " x 1 col., $330. Prepayment discount 5% for 6 issues; 10% for 12 issues prepaid at once. (All advertisers with PO Box addresses must supply permanent address and telephone number. Copy is subject to publisher approval.) The WIRELESS TELEPHONE TRANSMITTER model Mailing Information: Copy must be received by the publisher by the 20th of the third WTT -20 is only about the size of a dime, yet transmits both sides of a telephone conversation to any FM radio month preceding the cover date. Send Advertising material with check or money order with crystal clarity. Completely automatic. Uses power Modern Department, 76 N. Broadway, Hicksville, 11801. from the telephone line itself - never needs a battery! to: Electronics, Classified NY Up to '/e mile range. Tunes from 70mhz - 130mhz. Easy to assemble kit includes all parts and instructions. On- ly $29.98 tax incl. Call or send MO, VISA, MC for immediate delivery. L'IDEO F.LECTRO:`'ICS Single kit orders Include $1.50 S &H. FREE SHIPPING on orders of 2 or more. All orders shipped by U.S. Mail. COD add $4.00. Personal checks allow 21 days. PAY TV and Satellite Descrambling. 6 Ed. PROGRAMMABLE POWER SUPPLIES. DECO INDUSTRIES 100 pages covering 13 cable and 7 satellite sys- Proven schematics and well written details are BOX 607, BEDFORD HILLS, NY 10507 tems. Schematics, bypasses, descrambler de- provided on several digitally programmable 914. 232.3878 tection etc. Videocipher update (material not power supplies. Easy interface to PC and oth- CIRCLE 15 ON FREE INFORMATION CARD in the magazines) included. $14.95. MDS/ er devices or stand alone capability. $10PPD. sown CATALOG/HMOs MMDS Handbook. For microwave hackers J. BELL, 416 Dale Terrace, Clarksville, TN 1001 bargains in electronics. Save s $12.95. Cable TV. How systems work includ- 37042. ing two -way. $12.95. Experiments with Video - up to 50% call toll free 1- 800 -346- El LINEAR PARTS -Transistors: MRF454 cipher. Turn -ons $9.95. Build Satellite Sys- 2433 for ordering only. Order by $15, MRF455 $12, MRF477 $11, MRF492 tems under $600. $11.95. Any 3/$26. New cat- VISA/MC /AMX. No COD's. Missouri, II $16.75, MRF421 $22.50, SRF2072 $13, alog $1. Shojiki Electronics Corp., 1327M Ni- Alaska, Hawaii call 1- 816 -842-5092, SRF3662 $25, 3800 $18.75, 2SC2290 $19.75, agara St., Niagara Falls, NY 14303. COD's write McGee Radio, 1901 McGee 2SC2879 $25. Tubes: 6KD6 $10.50, 6LQ6 or II 716 -284 -2163. St., K.C., MO 64108. Postage for $9.75, 6LF6 $9.75, 8950 $16.75. Best Prices on catalog $1.00. CABLE and SUBSCRIPTION TV secret Palomar Road Noise Mics, Ranger AR3300. manual. Build your own DESCRAMBLERS, New 16 page Catalog listing radio /amplifier tricks -Channel Modification, PLL- Sliders, 1 1111 01/0. converters. Instructions, schematics for: Sine - wave, Inband /Outband Gated Sync Pulse, Peaking for Range, Hard -to -Find Linear SSAVI - (HBO, Showtime, Cinemax, UHF, Parts -Mail $1.00 to: RFPC, Box 700, San etc.) Send $8.95 to CABLETRONICS, Box Marcos, CA 92069. For Same Day Parts Ship- Where's my 30502ME, Bethesda, MD 20814. ment, Call (619) 744 -0728. CATALOG? CABLE TV CONVERTERS. Scientific At- HARDWARE, Software, Surplus Parts, lantic, Jerrold, Oak, Zenith, Hamlin. Many Solar Energy, Much more. Free Catalog. GIL others. Visa & M.C. accepted. Toll Free Electronics, Dept. 3, P.O. Box 1628, Soquel,

1 -800- 826-7623 B&B Inc. 10517 Upton Circle, CA 95073. Bloomington, MN 55431. $$S$$ Super Savings MSS SATELLITE DESCRAMBLING. Latest on electronic parts, components, supplies and methods of digital scrambling of the audio in computer accessories. Free 40 -page catalog video cypherll satellite television transmis- for SASE. Get on our mailing list. BCD Elec- sions. Covers Transmission format, key gen- tro, P.O. Box 830119, Richardson, TX 75083 or call 214 -343 -1770. What) You haven't seen the FREE DICK SMITH eration, and DES decoding. $10.95; CABLE - ELECTRONICS catalog' Or did someone steal TRONICS, Box 30502ME, Bethesda, MD your copy again? After all, who can resist 148 TOP QUALITY imported, domestic kits, sur- colorful pages crammed with 1000 -s of electronic 20814. plus, discount electronics, computer compo- goodies ranging from kits & components to com- nents. Free catalog. TEKTRASONIX, 80-50 puters & radio -controlled cars. The selection is DFSCRAMBLING manuals. VIDEOCIPHER incredible, the values are even better! Top it all off Baxter Ave., Suite 120, Elmhurst, NY 11373. with our exclusive 1 5 -page electronic data section, 11-$24.95. ORION-$19.95. LSASE brings and you'll have more than a catalog, more than a brochure. Satellite systems catalog $2.00 (re- Year reference: its a totally entertaining experience for TUBES: 594. Guarantee. Free Catalog. the electronic enthusiast, and its FREE! All we ask fundable) MICROTRONICS Box 2517 -M, Tube Tester $8.95. CORNELL, 4213 -17 Uni- is your name, address and $1.00 for first -class Covina, CA 91722. postage.What are your waiting for? Order yours versity, San Diego, CA 92105. today' STRANGE Stuff. Plans, kits, items. Build Sa- FREE RFI Technical Note tells how to keep tellite Dish $69. Descramblers, bugs, adult RF out of TV's, telephones, etc. with ferrite toys. Informational photo package $3. Re- beads. Palomar Engineers, Box 455, Escon- Box 212 -M, dido, CA 92025. Ir fundable. Dirijo Corporation, Lowell, NC 28098. LASERS and Nightvision surplus components. YES! Send toy r npy of ihr 1986 87 DSE w $ 1 00 for postage, FREE catalog, M.J. NEAL COMPANY, 6672 x,log today, Enclosed CABLE TV Secrets - the outlaw publication the OH 43146. Cable Companies tried to Ban. HBO, Movie Mallard Ct., Orient, Channel, Showtime, Descramblers, Converters, etc. Suppliers list included. $8.95. Cable Facts, Cn NPC -TF. RS Box 711 -ME, Pataskala, OH 43062. Address BASIC Computers, 10 lesson correspondence CABLE and Satellite Descramblers. Major course, $39.50. Certificate. Details free. Stare Zee brands, Catalog 3.00. Cabletech 3310 -10 W. AMERICAN TECHNICAL INSTITUTE, DICK SMITH ELECTRONICS,INC. 703H Bell, Phoenix, AZ 85023. Box 201, Cedar Mountain, NC 28718. PO Box 2249. Redwood City, CA 94063 L J 88 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com ilow .. .GW IM AM II MINN/ III 1- -4539 -344-3380 9103508982 DIG! KEY CORP AK, Puerto Rico800 218-081 Telex FAX 218 -881 TWX C O R P O R A T I O N - -6674 - 62827914 - - '

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The D'q.Key vo ume drucwm Mservpa charges are NM& to epPly. Mort :ems sold by D'Ni -Key may be combined for a VOID. dirAunt. llama that are not Erecountatve are 1d.11ú(10 by the suffix -ND oe.WepnaIpartlollowinsan number. After writing your° der, total allot the .nadaaable.ems end apply the rmoe ioe dhcount. To thiseu6taal, add the non-discountable items. Than add the service SERVICE CHARGES VOLUME DISCOUNT charge. We pays!! slipping and insurance to addresses in the U.S.A., Canada and Mexico when check or money order accompanies order. Dpi Key only ships orders within the continental U.S., Alaska, 0.00 - 9.99 Add02.00 8 0.00 - 99.99 NET Hawaii, anew and Mexico. 4 10.00..25.00 Add 0.75 8 100,00- 8249.99 Less 10% WILE ORDERING BY PRONE, CALL 180034445391 A8, call 219191.95741. BY MAIL SEND SOUR ORDER TO: DIGIKEY, P.O. Box 877, Vaal Riser Falls, MD 56701. $ 25.00449.99 Add 0.50 8 250.00- 499.99 Less 15% -899.99 Add 80.25 8999.99 Less You may pay b check, money order. Maser Charge, VISA or C.0.0. 0IGI.REY GUARANTEE: Any as w products purchased from Digi-Key that prove to be def °ClivewiII be replaced or refund 450'00 8500.00- 20% ed if returnedw thin 90 days from receipt whhecopy of your invoice. "'PRICES SUBJECT 70 CHANGE WITBOUT NOTICE." 41000 &Up No Charge $10005 Up Less 25%

CIRCLE 96 ON FREE INFORMATION CARD

www.americanradiohistory.com FINAL Closeout of new, Surplus, MS -DOS Cl) V/ /C.-4 T/O.S CABLE TV Software, and Manuals!! 10% Off with this EXPERT EXPORT REPAIR. PLAIN 40'S CABLE TV converters and descramblers. ad. Free Catalog. GIL Electronics, Dept. 2, TOO. MOBILES = $45.00, BASES = $55.00. Low prices, quality merchandise, we ship P.O. Box 1628, Soquel, CA 95073. PLUS $5.00 SHIPPING. LESCOM, 4.445 C.O.D. Send $2.00 for catalog. Cabletronics TI-99/4A Software /Hardware bargains. OUTWOOD, LADSON, SC 29456. Unlimited, P.O. Box 266-M, S. Weymouth, Hard to find items. Huge selection. Fast Ser- Mass. 02190 (617) 871 -6500. vice. Free Catalog. TYNAMIC, Box 690, VOICE DISGUISER, FM Transmitter, Tele- Hicksville, NY 11801 phone Transmitter and More! Catalog $1.00 INVENTORS (Refundable): XANDI, Box 25647, "F ", INVENTORS! Have idea for product or in- Tempe, AZ 85282. ELECTRONIC KITS vention, don't know what to do? Call AIM we Do It Yourself, HOBBY, EDUCATIONAL, COMMUNICATIONS PLANS, BOOKS, present idea's to manufacturers - Toll Free PROFESSIONAL 100 KITS to Choose From KITS! AM /FM broadcasting (licensed /unli- 1 -800- 225 -5800. Don't miss out on the ultimate in hobby, educational, censed), 1750 Meter transceivers, ham /CB and professional high quality, functional kits. amplifiers, surveillance bugs, more! FREE INVENTORS 'Light Dimmers EPROM Programmers catalog. PAN -COM, Box 130 -ME3, Paradise, INVENTORS! Can you profit from your Universal Timers Audio Input Selectors CA 95967. idea? Call AMERICAN INVENTORS COR- Power Amplifiers Alarms PORATION for free information. Over a de- Pre-Amplifiers Thermostates DIGITAL AUDIO Power Supplies Thermometers cade of service, 1- 800 -338 -5656. In Massachu- Light Computers AC Motor Controls DIGITAL AUDIO RECORDER Commo- setts or Canada call (413) 568-3753. Electronic ignitions Geiger Counters dore-64. Excellent Sound! Plans, P.C.B., & Inf ra-red Transmitters Mother Boards DRUM SOFTWARE: $19.95. KIT $49.95. Infra-red Receivers Extension Boards M/S('F- L L.4 .N'F. O L'S *Stereo- Decoders Interface Cards PostPaid, ORDER NOW!! TAD PAINTER, AM /FM Tuners Relay Cards P.O. Box 166055, IRVING, TX 75016. LEARN MORSE CODE IN 1 HOUR. Amaz- Door Bells OPTO Input Cards ing new easy technique. Moneyback guaran- Power/Switch Dimmer 'Quad Trlac Switch Card COMPUTER ROBOTS tee. $5. Bahr, 2549 Temple, Palmbay, FL To receive your catalog, send $3.00 to FISHERTECHNIK Robotic Computer Kits. 32905. Build ten different working models. Available HOBBY APEX® Screwdriving Bits: Phillips, Slotted, ELECTRONIC for Apple, IBM and Commodore. Valley Computers, 613 N. Idlewild, Kaukauna, WI Square Tip, Clutch Head, Reed- Prince, Torx, P.O. Box 1339, Claremont, NH 03743 414- 766 and School Pozidriv, Tri-wing and much more. Made in or call (603) 543.0033 54130. -3589. (Dealer PO's welcome). the USA. Precision machined, heat treated tool steel. Complimentary list. Don Shockey, 7 MILLION TUBES EPROM PROGRAMMING 5841 Longford Road, Dayton, Ohio 45424- 2940. Includes all current, ob- FREE catalog. Your software /data installed solete, antique, hard -to -find receiving, transmitting, indus- in (E)PROM of your choice. Fast, low cost ASIAN LADIES want correspondence for trial, radio/TV types. LOWEST service. Write /call: Romulus Microcontrol, friendship, marriage. SUNSHINE INTERNA- PRICES. Major brands in stock. Dept. C, Box 8669, Rockville, Maryland TIONAL, Dept. TW, Box 260, North Holly- Unity( Electronics Dept. M 20856; (301) 540-8863. wood, CA 91603. P.O. Box 213, Elizabeth, N.J. 07206

*0401 t PRCES SH ppING1 IPC ERfLES P OT 5COUN FSTTOc ns de hlesterCant C A Division of LJM TECHNOLOGIES INC. J PO Box 1540 13.8 VDC Haverhill. MA 01831 CO7i Telephone AC (8171373 -7750 VISA REGULATED POWER SUPPLY (lam These are solid state. fully regulated 13.8 vdc 10 AMP power supplies. Both feature 100% solid state SORRY. NO COD'S construction. fuse protection. and L.E.D. power SOLID STATE RELAY indicator U. L. listed. 40 CHARACTERS 5.;7 DOT HAT -. r. CONTROL: 3 - 32 vdc IEE 40 CHARACTER VACUUM FLOURESCENT DISPLAY MODULES. Display is 2 amp 4 LOAD: 140 vac 10 amp >e constant, amp surge $20.00 each blue-green. .24" high 5 x 7 dot matrix. ASCII coded for alphanumerics. On -board SIZE: 21/4" x W e 1/4" 3 amp Consta t, 5 amp surge 527.50 each microprocessor. Interfacing includes 8 -bit bidirectional bus and TTL serial I or $9.50 EACH 10 FOR $90.00 jumper selectable RS 232 for model 3601 I at 1200 baud. Requires only 5 VOC. PHOTO -FLASH Size: 10.75'L x 3'W x I'D. 26 pm conn.. 2' of cable. and 6 pgs. of data included. 48 KEY ASSEMBLY ml Model 5 3600 s 30.00 Each 10 G up S 25.00 Each RECHARGEABLE 170 330v CAPS FOR COMPUTER OR 75° ea. Three sizes Model S 3801 a 40.00 Each 10 G up a 34.00 Each HOBBYIST NI-CAD CAM PPC -170 400 mf 330v IBM PC -XT COMPATIBLE 150 WATT Power Supply. BATTERIES 1.00 ea. Cooling by on -board DC fan. New. in cartons. AAA SIZE1.25V 500mAH$1.8 CAIN PPC-400 Mt AA SIZE I 25V !get SPECIAL SALE PRICE e 80.00 Each 500mAH$1.85 800 ml 330v AA with solder tab $2.00 1.35 ea. NEW T.I. C SIZE 1 KEYBOARDS. OnginIly 1 S 10 S 5 2V 1200mAH $3.50 MC14011 CMOS Quad NAND Gate. 25pcs / Tube: -9 tubes 6 ea. Cup ea CATM PPC -800 SUB -C SIZE sa leer tab $3 50 used on computer,. the-.e k'.y- boards contain 48 P.S.T.meclh- D SIZE 2v 1200mAH $3.50 S. HITACHI Ii08880e MICROPROCESSOR. CPU with 2 MHZ Internal Clock. FLASHER LED anical switches. Terminate. t 5 volt operasOn 15 pn connector. Fame 4-...1T 2 for $ 5.00 Per Sleeve (9 pcs I 1 -9 a 23 / Sleeve 10 G up 1118 / Sleeve 8 OHMS 15 WATTS red jumbo T13/. EXTRA r size $1.00 each Ribbon Cable. 11 111- 2213-030. 22 Ga. stranded SPECTRA- STRIP 30 Conductor NEW GREEN FLASHER MINIATURE TOGGLE f 7/30 1 color coded cable. 100 ft. Rolls. in original cartons. List S 1 10.00/ Roll. SPECIAL CAT #LED -4G $1.00 SWITCHES SPECIAL SALE PRICE I 20 / Roll 5 G up S 18 / Roll VALUE XENON FLASH TUBE S.PD.T. S.PD.T. SOLID STATE DIFFERENTIAL PRESSURE TRANSDUCER. MICRO SWITCH (on -on) (on- off -on) s 143PCO2. 2.5 range. Supply range 7 to I6vdc. I to Bvdc cutout at Bvdc 3 4" long X 1/8" dia. Flash Solder lug lug : psi MODEL 853079 Solder supply. Measures gage. absolute. and differential pressure. Usable range _ 7.5 tube designed for use in terminals terminals and compensation. Oats included. R. LOUDSPEAKER compact camera flash units. 01.00 each osi. Built in signal conditioning temperature Ideal for experimentors. $1.00 each S YOUR PRICE S 35 Ea. 5 G up I 30 Ea 10 for 100 for List price over 65. R OHMS COIL 100 - 10,000 H1 CAT# FLT-1 2 for $1.00 $9.00 $$0.00 Power rating 15 watts max POWER MOSFETS AT SPECIAL PRICES LIMITED QUANTITIES ULTRA-MINIATURE D.P.S.T. LIGHTED Part Quantity Vds Id Rds Case Price Each 3.0 or ferrite magnet 5 VDC RELAY ROCKER SWITCH Fujitsu # 115 vac lighted No. e25 °C 1 on I Style 1 -9 10 -49 50 Cup Typical response range: rocker

- FBR211NED005M20 L - snap mounts in BUZ 21 1000 100 19.0 0.10 TO -220 9.50 8.50 7.50 High sensitivity CAT3I SK -815 $3.50 each h" x 1K" hole. BUZ 80 200 200 5.5 1.00 TO-220 6.00 5.40 4.80 COi._: 120 ohms $1.25 each Orange lens. 16 amp case of 8 525.00 CONTACTS lamp 10 for $10.00 BUZ 46 80 500 9.8 0.60 10-3 13.75 12.00 10.60 contact. $1.50 98 pcs @ 52.75 each. Mounts in 14 pin DIP socket se BUZ 64 200 400 10.0 0.40 10-3 14.80 13.00 11.40 LIMITED BUZ 84 500 800 5.3 2.00 10-3 21.50 18.90 15.80 QUANTITIES TOLL FREE ORDERS MINIMUM ORDER 0 MINI -PUSH BUTTON 100 38.0 0.055 TO -204 22.00 19.25 16.75 2N5764 50 1 -800- 826 -5432 W US A Sa005NIPPINGNG S. PS.T momentary NO C o 0 normally open (IN CA: 1 -800-258 -6666) ALL PRICES INCLUDE UPS or LISPS Shipping Within Continental USA FOREIGN 4" busting. INFO (213) 380 -8000 NINMNI INCLUDE SUFFICIENT each QUANTITIES ARE LIMITED. Phone in your order to insure availability sL'71in Red button 35C TWX - 5101010163 ALL ELECTRONIC ' for 53.00 SEND FOR OUR FREE CATALOG of Electronic G Hardware Bargains C AIf RES ADD 6 t 2

CIRCLE 17 ON FREE INFORMATION CARD CIRCLE 66 ON FREE INFORMATION CARD 90 / MODERN ELECTRONICS / March 1987 Say You Saw It In Modern Electronics

www.americanradiohistory.com AM /FM Radio IC W /Data Sheet (#2204) 15/1.00 BLITZ EPROM PROGRAMMER KIT / 508 Central Avg. 2N3643 (0-92 Silicon Gen (#2PN) 10/1.00 Attached To The Parallel Ponter Port Of An IBM PC, ` Slide Pots -1 Each 50K. 100K, 1.2#.2X, 5M- - .1.00 RO 1/VaaNiMd, N.J. 07090 XT, Or Compatible, The Blitz Programs 2716, 2732, ULN2231 (Delco DM50) Dual Preemp IC 2/1.00 (201) 854 008 2764, 27128, 8 27256 Eproms. Standard 8 Fast ?Mystery? Beg #1 The "OHM" Bag .1.00 Programming Algorithms Supplied. Voltage Selectable ?Mystery? Bag #2 The "Volt" Bag ..1.00 12.5V, 21V 8 25v. Diskette Included Provides Assembly ?Mystery? Bag #3 The "Circuit" Beg ..1.00 ART Instructions & Programming Procedures Kit -$69 95 M ?Mystery? Bag #4 The "Frequency' Bag 1.00 Assembled-99.95 - A Mystery? Bag #5 The "Tolerance' Bag 1.00 TOKO COILS FOR FEB 1984 TV PROJECT 74SCXX SERIES IC'S No Returns/Exchanges With Mystery Bags 41 Tako #'s BKAN-K5552AXX(2). #E52OHN- 3000023 IC Storage "Bug" Box 2.45 ' Cypher IV MlcroController Kit- $1 29.50 (.071uH) & L-2(12uH) Fixed. l Set Of 4PCS 6.00, 3 Sets LOW POWER, HIGH Heavy Duly Alligator Clips(10 Sets) .2.30 4 MHz 8.611 MICrOproCes5or

15.00, 10 45.00. 1 Sets SPEED ISO -CMOS(PIN Regular Alligator Clips (10 Sets) 1.80 1 NAT NS8073) Diode Ass t-65 Pcs Total -Includes 1N4148, 1N914, Wire Stoppers (Spring Loaded, Adjust.) .2.50 Control Basic Interpreter 0n-Chip 1N4004, 1N4007 1.95 COMPATIBLE TO LSXX 5" Needle Nose Pliers (Spring Loaded) 3.95 Auto-Start Operation At Power.On Zener Ass'665 Pcs Total- Includes Minimum 3 & SIMILAR 'TO HCXX) 4 1/2" Diagonal Curlers (Spring Loaded) 3.95 Fast 16.Bit Multiply And Divide Different 1W Devices 1.95 7450137 .45 74SC373... 35 Nut Driver Set For 3/16 ", 1M ". 5/16' .3/200 RS-232. Supports CRT 8 Serial Link LED Ass'IJumbo, Medium. Mini, Red. Green And 7450138. 45 7450374 60 Jeweler's Screwdrivers (4 Pcs) ..2.65 24 Bi- Directional I/O Lines 16255 Ai Amber -25 Pcs .1.95 74S0139 60 7450533 50 Desoldering Pump (Solder Sucker) 4.00 RAM Memory-2K Expandable To 16K Resistor Ass1-1,000 Pcs 35 Values Minimum. Popular 7450237 60 7450534.. 50 Replacement Tips For Solder Sucker 2/3.00 Eprom Memory-Expandable To 1 bK Values (1K, 10K, 100K) Included. Mostly 1/4 & 112W. 7450239 60 745C540 50 25W Precision Soldering Iron .5.00 Built In Eprom Programmer Some 2W. Lots 01 Precisions. Film. 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Power Supply and Balun $36.50 For Jumbo .15/1.00, 100/6.00 1,000uF 75V Axial 75 22 Or 27 AWG Wire (Specify) 5011.00 Assembled Version $57 50 Switch Ass'I- Slides,Rockrs,Toggls 10/1.95 3,200uF 50V Twist Lock 1.00 _ Axial Lybc 75 Disc Cap Assi (1.5p1 To .47uF) ..50/1.95 3,300uF 50V Mylar Cap Assi(.001uF To .33uF) 25/1.95 5,000uF 40V Computer Grade (Mallory) 2 50 Terms MICRO-MART accepts Visa MC and tefephOne COD's Minimum order 510 00 Shipping - Monolithic Cap Asst - 251f 95 Dip Mica Ass'I(Approa. 10 Velues) 15/1.95 D s orders. S2 00 Canada and other countries 53.50 ( minimum ) Shipping rate adjusted where Crystal Clock Oscillator 14.9760 MHZ .50 Adjustable Coil/Fixed Choke Asst 10/1.95 applicaDk NJ residents add 6% sales tax Triac (400V 6A To-220), Tic#216A 2/1.00 UCN4116B- OSC/Freq Div Clock IC 5/1.00 SCR (.5A 30V To-92), TIC#44 5/1.00 CIRCLE 37 ON FIFE INFO. CARD IC00-IUOT 501 CENTRAL AVE., ESTFIELD. NJ 07000 (201( 6544008

Logic Signal Measurements (from page 21)

within circuit amplitude limits, be- When problems arise, it's general- ference is bothering your measure- ware of overshoot. Momentary hard ly because a stably triggered display ments, you can build a 60 -Hz filter saturation caused by pulse overshoot cannot be achieved. Signal noise or and use it at the channel -1 scope in- can still extend device storage time. jitter are causing the trigger point to put. You'll need to set the scope for a Overshoot can do even worse jump around on the signal. Thus, the dual -trace display with triggering on things to voltage-sensitive devices. signal jumps around on the display. channel 1 and the unfiltered version Perhaps you'll have the opportunity Most triggering problems can be of the signal fed to channel 2. The fil- to experiment with high -speed solved if the scope has some reject tered channel -1 waveform serves on- CMOS devices. The tendency here is modes provided in the triggering sec- ly as a triggering device, and actual to tweak circuits for the highest slew tion. For example, display drift measurements must be done on the rate (risetime) pulses possible as part caused by 60 -Hz interference from channel -2 display of the unfiltered of milking more speed out of the cir- lights can be eliminated by using a version of the waveform. cuit. But fast slew rates often cause low- frequency reject mode. A high - Such external filtering for a stable overshoot. In CMOS circuits, ex- frequency reject mode is useful for trigger signal can get you by in some ceeding logic swing limits with over- eliminating interference from local cases. But it does require building a shoot can result in latchup, which radio stations. A noise reject mode special filter for your particular causes the circuit to burn out. emphasizes the peak -to -peak ampli- needs. It also uses up one of your tude of the signal coupled to the trig- scope inputs just for triggering pur- Triggering Tricks gering circuit and improves trigger- poses. For more widespread mea- Making any of the above measure- ing on signals in the presence of elec- surement needs, it is far more conve- ments or waveform observations trical noise. nient to have a selection of measure- presumes you can get the digital sig- If your scope does not have these ment modes and triggering features nal displayed on the scope screen. convenience features, you can some- built into the scope. This allows you Sometimes that's easy. Sometimes times emulate them with external fil- to spend more time on your project it's not. tering. For example, if 60 -Hz inter- and less time fiddling with the scope.

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