-~ PANEL METERS by • III' 11'1 " II ' " 'II II I ,.(1 OPERATOR'S \, .. \ 'I' I' ~~:.' ~ MANUAL ~ ,~, ~ ~ - - ~'- _II. '7. VOI.,..oHM-MlLLIAMME'I'ER MODELS 25,35, 45, 55 MODELS 27, 37, 47, 57 SIMPSON MODERNISTIC 3!" ROUND. ACC URAC Y 2~ MODEL 260 3~" RECTANGULAR ·CLEAR·VUE­ SC ALE LEN GT H: 1-7/8" ACCUR ACY : 2~ BU ILT TO SPE C IAL ORDER AL SO AS MODELS 125, 135 145 AND 155 - ALL 2!" SC AL E LENGT H: 2-9/16" It!". 5!" SIZES 2P. 3P. ROUND . SC ALE 1-7/8 " ~ r~1,~ 7 ~iiiiiiiii (® I!!I!li MODELS 27, 37.57 MODELS 29,39,49,59 ILLUMINATE D MODELS 127, 137, 147, It!" RECTANGULAR 3!" RECTANG ULAR 157. 2!" RECT ANG UL AR SIMPSON ELECTRIC COMPANY ACCUR ACY : 2$ ACCU RAC Y: 2$ ACCUR ACY : 2$ SC ALE LENGTH: 3-29/32" SC ALE LE NG TH : 1-5/ 16" SCALE LENGTH: 1-7/8" 5200 W. KINZIE ST., CHICAGO 44, ILLINOIS. EStabrook 9.1121 IN CANADA, BACH·SIMPSON, LTD., LON DOH, ONTARIO NEA RLY 800 DIFFERENT S I ZES AN D KINDS OF S IMP SON PANEL METERS ARE AVAILABLE F RO M YOUR ELE CTRONIC PART S JOBBER. WHETHER YOU NEED ONE PANEL METE R ••••• OR A DOZEN ••••• LOOK FOR THE FAMI LIAR OR AN GE COLORED S IMPSO N BOX . FOR FURTHER INFORMATION WRITE SIMPSON ELECTRIC Copyright 1955. Simpson Electric Co.• Printed in U.S.A. CO •• 5200 W. K IN Z I E ST • • CH I CAGO Itlt. I LL •• ESTEBROOK 9-1121. T ABLE OF CONTENTS T ABLE OF CONTENTS SECTION III FUNCTIONING OF PARTS Bias of Power Detector ...... 35 Schematic Diagram .................. 20 Model 260 as a Condenser Tester. 35 D.C. Volcmeter Circuit - 20,000 Ohms Per Volt. 20 Initial Deflection Not Present ... 35 Resistance of Multiplier Resistors ...•.... 20 Positive Jack to Positive Condenser Terminal 36 A.C. Voltmeter Circuit - 1000 Ohms Per Volt. 21 Should Read About. 5 Megohm ..... 36 A.C. Rectified by Copper Oxide Rectifier. 21 Paper Condensers ............. 36 A.F. Output Meter ... 22 Condensers From .001 Mfd. to 1.0 Mfd. 37 Reading A.C. Voltage 22 Descriptive Tables ............ 38 Effective Resistance. 23 2.5 Volt Range ....... 23 SECTION VI SUPPLEMENTARY DATA Volume Level Meter. 23 RMA Resistor Color Code Chart ..... 39 Conversion of Scale. 24 RMA Mica Capacitor Color Code Chart. 40 Output Meter .... 24 RMA Condenser Marking Code ... 41 D.C. Ohmmeter ... 24 Volts-Decibels Conversion Table. 42 D.c. Milliammeter and Ammeter. 25 Capacitive Reactances. 44 Audio Frequencies. 44 SECTION IV MAINTENANCE Radio Frequencies .. 44 Do Not Drop Your 260.......... 27 Make Proper Settings Before Use .. 27 Battery Replacement .................. 27 Pointer Won't Zero on Rx1 and RxlOO Ranges. 28 Pointer Won't Zero on Rx10,000 Range. 28 How to Replace Batceries. 28 Parts List .................. 32 SECTION V MODEL 260 SPECIFIC APPLICATIONS General. .......... 34 Measuring Grid Currents. 34 F .M. Alignment ..... 34 A.V.C. Diode Circuits. 34 High Mu Plate Voltage. 35 4 ') f¥oJWW-oJUI LIST OF ILLUSTRATIONS WORLD FAMOUS PAGE As the purchaser of a Simpson 260, you are now the owner Fig. 1 Simpson Volt-Ohm-Milliammeter Model 260 2 of the most famous testing instrument in the world. Com­ 2 Simplified D.C. Volcmeter Circuit. Fig. 21 pact, of unusually high sensitivity (50 microamperes full Fig. 3 Simplified A.C. Voltmeter Circuit ...... 22 scale), the Model 260 has earned its top ranking reputation 4 Simplified Output Meter Circuit........ Fig. 23 as the result of quality construction joined to exceptional Fig. Ohmmeter Circuit with Selector Switch in 5 engineering versatility. This engineering superiority is, in Position Rx 1 ................. 24 turn, the product of invaluable years of experience with Fig. 6 Ohmmeter Circuit with Selector Switch in every single unit comprising the complete assembly. Position Rx 100 ................ 25 . In choosing the Simpson 260, you have concurred in Fig. 7 Ohmmeter Circuit with Selector Switch in the verdict of over 300 governme nt agencies and Position RxlO,OOO ....... ... 25 university laboratories which, long before World War Fig. Sa Simplified Microammeter Circuit .... 26 Fig. 8b Simplified Milliammeter and Ammeter II, and all through it, purchased it. in quantities un­ Circuit. ................. 26 equalled by any competitive instrument. Ie served Fig. 9 Model 260 Schematic Diagram...... 29 on every batdefront and in every branch of our Fig. lOa Model 260 Parts Layout - Rear View.. 30 armed services. Model 260 Parts Layout - Rear View of Fig. lOb MANY FEATURES IN "260" Front Panel ............... 31 In no other instrument of its kind do you find features such Fig. 11 Model 260 Used as Condenser Tester.... 37 Fig. 12 RMA Resistor Color Code Chart ....... 39 as are contained in the Simpson Model 260. Ics trim, scien­ Fig. 13 RMA Mica Capacitor Color Code Chart ... 40 tific appearance -- the 4];i" modernistic instrument, the heavy bakelite case, the neat bakelite .panel -- gives evi­ dence of inner quality. These hidden features are too nu­ merous to mention here, but your pride in your new instru­ ment will grow as you learn of them. Parts are assembled and placed in position so they cannot become loose or detached from their original positions. All the sub-assem­ blies are mounted on specially designed bakelite pane ls, or on a specially designed sub-panel, made and engineered expressly for a specific function in the Model 260. 6 7 SIMPSON BUILDS ITS OWN TEST EQUIPMENT When you purchase Simpson test equipmenr, you get equip­ OPERATOR'S MANUAL menr made almost enrirely within the various planrs of our Company. Each component pan of the 260 has been de­ SIMPSON MODEL 260 YOLT·OHM·MILLIAMMETER signed and completely rooled and manufactured in our own planrs, with the exception of the resistors and one or two SECTION I other functionally less important parts. The Model 260, GENERAL DESCRIPTION like all other Simpson testers, is not an assembly job made up from purchased pans such as is true of the majority of The Simpson Volr-Ohm-Milliammeter Model 260 offers the testers offered on the market. service dealer a small, compact and complete instrument with high sensitivity for testing and locating trouble in all We are by far more self-conrained than any other manufac­ types of circuits. The large four and one-half inch meter turer of test equipmenr. This is your assurance that the provides a long scale that is easy to read, and the compact testers we offer will not quickly become obsolete. Our arrangemenr of the conrrols allows the overall size of the tremendous investmenr in expensive production rools is bakelite housing ro be comparatively small for maximum your safeguard against obsolescence and further assurance portability. of unvarying quality. Each unit is supplied with an operator's manual and one Here at Simpson we do not think of making instrumenrs set of red and black test leads with insulated clips. merely to sell. We think of making instrumenrs ro serve. Our inrerest in your Model 260 and in your satisfaction The electrical circuit is designed to give maximum insur­ with it never ceases. That is the reason for this Operator's ance against inaccuracy and damage to the componenr Manual. We want you to know how to get the most from pans. Highly accurate carbofilm resistors are used ro in­ your 260. sure long life and dependability, and these are firmly held in place in a special bakelite housing designed for this The Model 260 is a rugged instrumenr and will withstand a purpose. The entire assembly is truly rugged and can well great deal of abuse. We urge you, however, to treat it with withstand the wear and tear of the service work for which care as its mechanism is actually more delicate than that it is designed. of a watch. If you will keep it clean, free from conrinuous severe vibration and avoid dropping it, your Model 260 will ACCURACY give you a lifetime of accurate, dependable service. Accuracy is 3% D.C. and 5% A.C. of full scale deflection. 8 9 GENERAL DESCRIPTION GENERAL DESCRIPTION D. C. RESISTANCE MEASUREMENT RANGES 0-2000 ohms (12 ohms cencer) D. C. VOLT AGE 0-200,000 ohms (1200 ohms cencer) 0-2.5 voles 0-20 megohms (120,000 ohms cencer) 0-10 voles CURRENT IN D. C CI RCUITS 0-50 voles 20,000 ohms per vole sensieiviey 100 microamperes 0-250 voles 10 milliamperes o - 1000 vole s 100 milliamperes 250 millivoles 0-5000 voles 500 mi lliamperes A. C. VOLTAGE 10 amperes 0-2.5 voles D. C. VOLT AGE MEAS UREME NTS 0-10 voles D. C. vole age is measured by applying ehe unknown volcage 0-50 voles 1,000 ohms per vole sensieiviey co ehe meeer ehrough suieable ineernal series resiseors. 0-250 voles The meeer has a full scale sensieiviey of 50 microamperes 0- 1000 voles ae 100 millivolcs wieh an incernal resiseance of 2,000 ohms, 0-5000 voles giving ehe inserumenc an overall sensieiviey of 20,000 ohms A. F. OUTPUT VOLTAGE per vole. 0-2.5 voles A. C. VOLTAGE MEASUREMENTS 0-10 voles A. C. voleage measuremencs, including oueput and decibel 0-50 voles 0.1 Mfd. internal series condenser readings, are made possible by ehe use of an incernal cop­ 0-250 volts per oxide receifier conneceed in series wieh ehe meeer. A 0-1000 voles precision wound incernal shunt resiseor is conneceed in VOLUME LEVEL IN DECIBELS parallel wieh ehe meeer in order co obeain a sensieiviey of ohms per vole. -12 co + 3 decibels 1,000 o co +15 decibels Calibrated for reference level D.