Apple /// Computer Information • Apple /// Level 2 Service Reference Manual É Apple /// Computer Information Apple /// Servîce Reference Manual Theory of Operation Servicing Information Written by Apple Computer1982 Apple Computer Inc • 1982 Page 0001 of 0730 PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor Apple /// Computer Information • Apple /// Level 2 Service Reference Manual pic vîcc APPLE III SERVICE REFERENCE MANUAL Apple Computer Inc • 1982 Page 0002 of 0730 PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor Apple /// Computer Information • Apple /// Level 2 Service Reference Manual ppcomp To the Reader, This manual was developed for all the A/// Service Technicians at our Level It Regional Service Center. The intent of this book is to help you understand and repair the AppleI/I. The book is partitioned into two sections: Theory of Operation and Servicing Information. There is sufficient information in this manual so that an inexperienced technician can be productive in a short time. This manual should help you understand and appreciate the AppleI/I. In Appreciation: Although many people have helped me with this manual I wish to particularly thank the following people for their contribution to this manual: Bill Holman Wendell Sanders Mike Fallon Rick Hoiberg Ed Goodwin Sandy Sanford Peter Quinn Thanks! Bob Cummings Apple Computer Inc • 1982 Page 0003 of 0730 PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor PDF compression, OCR,web optimization using awatermarked evaluation copy of CVISION PDFCompressor Apple Computer Inc•1982 everytableshoot1f you ofyourfacet are contents machine, interestedof APPLEthe (shown Appleyou in shouldbelow),howI/I.II Ithe haveREFERENCE LikethisApple this newcomprehensive I/I manual.condition, works, MANUAL Asor manualbinder, youif youcan covers 17 wantsee chapters, fromtovirtually trouble the Apple ///ComputerInformation•Level2ServiceReferenceManual TARIE OF COI1TENTS VIDEODISP1OY460 SISPLAYpages Iodes LOGIC(8-1/2x 11),two diagnosticBuilt-InThe System I/O Monitor Locationsdiskettes $150.TABLES & ILLUSTRATIONS ThEORY OF OPERATION BO40Inc Choracter CiaractorroductChoracter Ion AppleAppleBlack &/1/j) Ahite AppleI/I ThePeripheral Joystick ConnectorI/O Ports SignalPinout DvocriptlnR AISEhIElSyste. System Systo.Functional BSockBlock Block DiagramDiagtam Diagram (Illustration)- Detailed (Illustration) INTRODUCTEONTheSispilfiedCenerai Mein De.cription Logic Punctionsi Board Description AppleSuperModicaBlack hHire./1/ ResolutionWhiteRires Apple Hiree 16I/I Color Graphics AppleI/I SCHEMATICAnnotatedROM ListinHe DIAGRAMS Schesatic Diagrams The Apple12S Volt Volt 1ff/11Memory MemoryMainDetabied BoardLogicBoard System (128EBoard (126K Functional(Module)Configuration) Configuration) Block Diagram The AppLeMemoryKeyboardDisk DriveI/I Board FCBPower Supply iNPUT/OUTPUTDescrtptVideoSuper AppendinHires ion AppleI/I DISKTheoryAnalogDisk SUBSYSTEM Conditioning 0fCard Ope tattoo Circuit TheindirectRAS/CASBlockSimplified Apple Diagrss Addressing Decode I/IMesory MemoryMemory Logic Address (Listing) AddressflapBlock Block Diagram Logic Diagram K5ORYMemorySimplifiedintroduction & MENORY Addressiug Mesozy En ADDRESSING the Login AppiaBlock Flow/1/Memory TheAddressingInterruptsinterface Input ControlOperation the I/O lignais SERVICING INFORMATION MemoryAddressMemoryApple & Memoryi/I MapLogicMemory Space Addressing Truth Map Allocations Table Appendis AlternateRAS/CASMemoryThe Pronessor AddressDecode Stack )twltipiemer theSystemThe A//IOutput Timiog Joystick Operation TESTDHCIII b TROUBLESHOOTINGFinal Test Procedure HowThe Apple 5to Volt READ/1/ IIIMemory PROMMemory (ROM) Board Board Logic(2S() (12W)(5V) Empressions TM!VusVIAGeneralMemory VERSATILE Functional6522 & Fishesory I DencriptlnnaRTERFACE Description Addresaing ADAPTER Appendices TREElectronicTheKeyhoardReading KEYBOARD KeyboardApple the Codez CircuitKeyboard[ Emulation De.crtptioo Mode TheAppleS16 Volt Sector Apple /1/Mrmury SinkTroubleshooting/1/ TroubleshoOting BoardI/IFinal Ram TestTroubleshooting (Mrdule Flowchart(bOOT) Lanci) (Component) Procedure VEAAddressingVIABlockMPSRASI FlEXPRIE biagra. Registers LogicInternal 6522 of ispreasiosEhe VIARegioterRegister 6522 Iterual VIASummary Register VIA6522loterrupt (FFDX)Appendices(FrEE) VIA Operationiovirnnnant asControl KeyboardThe RepeatReset Light Function Function PARTSWIREApplepe LISTLAYOUT iii/1/ IndentedtcriW AND PARTS Bill tit LOST nf ion Macerlain ACIAACtAACEATheVIA ACEA Appendices Command StatueCootroi Block ReRleter Register Register Diagram THEComa.ndStatusThe AdAInterfsce 6551 Register Register Asynnhomous Adapter Conicatione POWERSchematicDetailedBowTheParts ABacic itSUPPLY List s.orbiile7/I Hardware SwitchingPower Description FouetSupply Supply MODULEWireApple List I/IREPLACEMENTIIII/I Asaembly ModuleDealer SerniceReplacemant DrawingsPROCEDURES Diagnoatics bProcedures ASSEMBLY Reference DRAWINGS VideoSA//IFreqoescyMainACIA to Systes2 Clock Pin11hzState Configuration Divider Timing14Mhz GearshiftCounter CIrcuitDiagramsCircuit SISTiMMainSimpleControl Clock CLOCKS SerialRegister ClAM k Port TIMING AltA))ComponentThe EISULATIOB EmulationColor VideoLayout Restrictiçoa Connector CENtRALAppleIIII/I/1/ APPENDIXSystemLogic SignaiOverviewMonitor Source VideoHiresHArcaApple ScanAppendis Mode Decode///Mode Video Page LugeROM Logic 2, 1, B/U, B/U, Bloch 280 280 DiagramX X 192192 Page 0004 of0730 FrequencyQ Timing Divider The SpeakerHigh-Resolution Crophics (Hi-Ken) Mode MainPromHow to(ROM)Logic Read Board Logic Pros (Boa)EmpressionsCircuit Logic Function Empressions Areas 280280 EX 192192 ColorCoiot HiresBites Mode Page 12 VerticalHorizontalVideoRASAo,RVE° PRE1K, (Row Freeze Horizontal Section AddressbSection CiM bStrobotSelect)) Vtrtical State Counters AutoetartStrobeAnalogA/DInput/OutputThe CassetteSelection Output Inputs ROM/Monitor SntertsceSpecial ROM brat ions Ascii Conversion Tables Ahite.SuperDuper HiresRiresTest PageModelode¡cIID Page MORt!Page 2I Apple /// Computer Information • Apple /// Level 2 Service Reference Manual TABLE OF CONTENTS PAGE SECTION I. THEORY OF OPERATION CHAPTER 1. INTRODUCTION Genera]. Description 1.l Simplified Functional Description 1.4 The Main Logic Board 1.4 The Memory Board 1.6 The Keyboard PCB 1.7 The Disk Drive 1.7 The AppleI/IPower Supply 1.7 CHAPTER 2 MEMORY & MEMORY ADDRESSING Introduction to the AppleI/IMemory 2.1 Simplified Memory Logic 2.1 Memory Addressing: Block Flow 2.4 The Processor 2.4 Memory Address Multiplexer 2.6 RAS/CAS Decode 2. 6 Alternate Stack 2.10 Memory & Memory Addressing Appendices 2.12 CHAPTER 3 THE VERSATILE INTERFACE ADAPTER nera1 3.1 VIA6522Pin Descriptions 3.1 VIA Functional Description 3.6 Interrupt Operation 3.8 6522VIA Environment and Control 3.10 VIA (FFDX) 3.12 VIA (FFEX) 3.15 VIA Appendices 3.18 CHAPTER4 THE ACtA ie 6551 Asynchonous Communications Interface Adapter 4.1 Status Register 4.3 Command Register 4.4 Control Register 4.5 Simple Serial Port 4. 6 CHAPTER5 SYSTEM CLOCKS & TIMING Main Clock CI4M 5.1. Frequency Divider 5.1. "Q" Timing 5.1 HPE* Freeze 5.5 Ax, PREIM, & C1M 5. 5 RAS (Row Address Strobe[Select]) 5.5 Video Horizontal & Vertical State Counters 5.7 Horizontal Section 5.7 Vertical Section 5.10 iii L Apple Computer Inc • 1982 Page 0005 of 0730 PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor Apple /// Computer Information • Apple /// Level 2 Service Reference Manual " CHAPTER- 6 IVIDEO DISPLAY LOGIC Display Nodes 6.1 mt roduct tori 6.2 40 Character Apple ] 6.2 40 Character AppleI/I 6.3 80 Character Black & White AppleI/I 6.3 Black & White Hires 6.4 Medium Resolution 16 Color Graphics Apple/1/ 6.4 Super Hires AppleI/I 6. 5 AppleI/iHires 6.5 Super Hires AppleI/I 6.7 Video Appendix 6.9 CHAPTER 7 INPUT/OUTPUT Description 7.1 Interface Control Signals 7.1 Interrupts 7.2 Addressing the I/O 7.2 The Input Operation 7.3 The Output Operation 7.3 System Timing 7.3 the A//I Joystick 7.5 CHAPTER 8 THE KEYBOARD he Keyboard a.i Reading the Keyboard 8.1 Keyboard Codes 8. The Applej fEmulation Mode 8.? Electronic Circuit Description 8.7 The Repeat Function 8.8 The Reset Function 8.8 Keyboard Light 8.8 CHAPTER 9 POWER SUPPLY The Applei/IPower Supply 9.]. The Basic Switching Power Supply 9.1 How it works! 9.3 Detailed Hardware Description 9.6 Schematic 9.9 Parts List 9.10 Component Layout 9.13 CHAPTER 10 AJ[ EMULATION A] [ Emulation Restrictions 10.1 The Color Video Connector 10.2 The High-Resolution Graphics (Ej-Res) Mode 10.3 The Speaker 10.3 The Cassette Interface 10.3 Input/Output Special Locations 10.4 AID Selection 10.4 Analog Inputs 10.5 Strobe Output 10.5 Autostart ROM/Monitor ROM 10.5 Apple Computer Inc • 1982 Page 0006 of 0730 PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor Apple /// Computer Information • Apple /// Level 2 Service Reference Manual The System Monitor lO. 6 Built-In I/O Locations 10.8 Peripheral I/O 10.10 The Joystick Ports 10.11 Peripheral Connector Pinout 10.14 Peripheral Connector Signal Description 10.15 ROM Listings 10.18 CHAPTER 11 SCHEMATIC DIAGRAMS Annotated Schematic Diagrams 111 CHAPTER 12 DISK SUBSYSTEM iory Of Operation 12.]. Disk Conditioning Circuit 12.]. Analog Card 12 4 SECTION II. SERVICING INFORMATION CHAPTER 13 TESTING & TROUBLESHOOTING Apple/1/Final Test Procedure 13.1 16 Sector DiskI/IFinal Test(1000T) 13.9 AppleI/ITroubleshooting (Module