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COMPAQ DESKPRO 386
Personal Computer
MAINTENANCE AND
SERVICE GUIDE
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NOTICE The information in this guide is subject to change without notice. COMPAQ COMPUTER CORPORATION SHALL NOT BE LIABLE FOR TECH- NICAL OR EDITORIAL ERRORS OR OMISSIONS CONTAINED HEREIN; NOR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM THE FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL. This guide contains information protected by copyright. No part of this guide may be photocopied or reproduced in any form without prior written consent from Compaq Computer Corporation. © Copyr
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ii WARNING This equipment has been certified to comply with the limits for a Class B computing device, pursuant to Subpart J of Part 15 of FCC Rules. Only peripherals (computer input/output devices, terminals, printers, etc.) certified to comply with the Class B limits may be attached to this computer. Operation with noncertified peripherals is likely to result in interference to radio and TV reception. WARNING This equipment generates, uses, and can radiate radio frequency energy. If
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iii NOTICE Compaq Computer Corporation requires that all peripheral devices be connected to this computer via shielded cables with metal RFI/EMI connector hoods. WIRE TYPE: Multipaired overall-shielded; Belden #98XX; Alpha #54XX; or equivalent. CONNECTOR HOOD: RFI/EMI metal shield; AMP #74517X-X; or equivalent. It is important that the chassis ground of any peripheral device be connected to the computer chassis. An Alpha #1221 flat-braided strap is sufficient. This strap is not necessary
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iv PREFACE The COMPAQ DESKPRO 386 PERSONAL COMPUTER MAINTENANCE AND SERVICE GUIDE is a troubleshooting, maintenance, and repair guide that can be used as a reference when servicing the COMPAQ DESKPRO 386 Personal Computer. All troubleshooting and repair procedures are detailed to allow subassem- bly/module-level repair only. CAUTION Because of the complexity of the individual boards and subassemblies, Compaq Computer Corporation strongly recommends that you do not attempt to make field rep
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v SUMMARY OF TEXT The COMPAQ DESKPRO 386 MAINTENANCE AND SERVICE GUIDE con- tains the following eight chapters: Chapter 1 OPERATING AND PERFORMANCE SPECIFICATIONS pro- vides operating and performance specifications for the COMPAQ DESKPRO 386 Personal Computer. Chapter 2 POWER-ON SELF-TEST (POST)/PROBLEM ISOLATION describes the internal system diagnostics programs that run automati- cally when you turn on the system. A flowchart is provided for identifying and correcting problems that can
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vi Chapter 6 ILLUSTRATED PARTS CATALOG contains illustrated part breakdowns, order numbers, and part names for the COMPAQ DESKPRO 386 Personal Computer. Chapter 7 REMOVAL AND REPLACEMENT PROCEDURES describes how to remove and replace subassemblies for the COMPAQ DESKPRO 386 Personal Computer. Chapter 8 JUMPER SETTINGS AND SWITCH SETTINGS provides de- tailed information for setting jumpers and switches on the COMPAQ DESKPRO 386 Personal Computer.
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vii REQUIRED TOOLS AND SUPPLIES To service the COMPAQ DESKPRO 386 Personal Computer, you need: □ Torx T-10 screwdriver □ Torx T-15 screwdriver □ Small Phillips screwdriver □ COMPAQ Personal Computer ADVANCED DIAGNOSTICS Diskette Version 5.XX (part no. 108137) □ Formatted scratch diskette(s) □ 25-pin printer loopback plug (part no. 100755-001) □ 9-pin serial loopback plug (part no. 102999-001) □ 80387 coprocessor removal tool (part no. 108492-001) Optional tools are: □ Memory chip insertion to
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viii ADDITIONAL INFORMATION The following documentation and related software are available to support the COMPAQ DESKPRO 386 Personal Computer. Associated Documentation: □ COMPAQ DESKPRO 386 PERSONAL COMPUTER OPERATIONS GUIDE □ COMPAQ DESKPRO 386 TECHNICAL REFERENCE GUIDE VOLUMES I and II ® □ MS-DOS /BASIC VERSION 3.1 REFERENCE GUIDE ® □ MS-DOS /BASIC VERSION 3.2 REFERENCE GUIDE ® □ MS-DOS /BASIC VERSION 3.3 REFERENCE GUIDE □ Service Advisories □ Service Bulletins □ HOW TO DO BUSINES
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ix CONTENTS Chapter 1 OPERATING AND PERFORMANCE SPECIFICATIONS 1.1 INTRODUCTION 1-1 1.2 COMPAQ DESKPRO 386 PERSONAL COMPUTER 1-2 SYSTEM UNIT 1.3 COMPAQ ENHANCED KEYBOARD 1-3 1.4 COMPAQ 84-KEY KEYBOARD 1-3 1.5 COMPAQ DUAL-MODE MONITOR 1-4 1.6 COMPAQ COLOR MONITOR 1-5 1.7 COMPAQ VIDEO GRAPHICS COLOR MONITOR 1-6 1.8 COMPAQ VIDEO GRAPHICS MONOCHROME MONITOR 1-8 1.9 360-KBYTE 5¼-INCH DISKETTE DRIVE 1-10 1.10 1.2-MEGABYTE 5¼-INCH DISKETTE DRIVE 1-12 1.11 1.44-MEGABYTE 3½-INCH DISKETTE DRIVE 1-12 1
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x Chapter 2 POWER-ON SELF-TEST (POST)/PROBLEM ISOLATION 2.1 INTRODUCTION 2-1 2.2 POWER-ON SELF-TEST (POST) 2-1 2.3 PRELIMINARY STEPS TO PROBLEM ISOLATION 2-2 2.4 PROBLEM ISOLATION FLOWCHART 2-2 Chapter 3 SETUP PROGRAM 3.1 WHEN TO RUN SETUP 3-1 3.2 HOW TO RUN SETUP 3-2 Chapter 4 ADVANCED DIAGNOSTICS PROGRAM 4.1 PRELIMINARY STEPS 4-1 4.2 MAIN MENU 4-2 4.3 ADVANCED DIAGNOSTICS PROGRAM 4-4 4.4 TEST SELECTION MENU 4-5 Chapter 5 ERROR MESSAGES AND CODES 5.1 INTRODUCTION 5-1 5.2 POWER-ON SELF TEST ERR
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xi Chapter 6 ILLUSTRATED PARTS CATALOG 6.1 INTRODUCTION 6-1 6.2 SPARE PARTS LIST, U.S. 6-2 6.3 SPARE PARTS LIST, INTERNATIONAL 6-9 6.4 PARTS LIST 6-10 6.5 300-/600-MEGABYTE FIXED DISK EXPANSION UNIT PARTS LIST 6-21 Chapter 7 REMOVAL AND REPLACEMENT PROCEDURES 7.1 INTRODUCTION 7-1 7.2 MONITOR 7-2 7.3 KEYBOARD 7-5 7.4 POWER FUSE 7-6 7.5 PRELIMINARY STEPS TO INTERNAL REMOVAL AND REPLACEMENT PROCEDURES 7-8 7.6 SYSTEM UNIT COVER AND INTERNAL CONFIGURATION 7-9 7.7 POWER SUPPLY 7-12 7.8 BATTER
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xii 7.15 MASS STORAGE DEVICE(S) 7-33 7.16 SYSTEM BOARD 7-39 7.17 INTEL 387 COPROCESSOR 7-45 7.18 LOST KEY 7-49 7.19 300-/600-MEGABYTE FIXED DISK DRIVE EXPANSION UNIT 7-50 Chapter 8 JUMPER SETTINGS AND SWITCH SETTINGS 8.1 INTRODUCTION 8-1 8.2 SYSTEM BOARDS 8-2 8.3 32-BIT SYSTEM MEMORY BOARD 8-6 8.4 .5- TO 2-MEGABYTE 16-BIT MEMORY EXPANSION BOARD 8-8 8.5 1- TO 2-MEGABYTE AND 4- TO 8-MEGABYTE 32-BIT MEMORY EXPANSION BOARD 8-10 8.6 ESDI FIXED DISK DRIVE CONTROLLER BOARD 8-12 8.7 MULTIPURPOSE
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xiii Chapter 9 MASS STORAGE CONFIGURATIONS 9.1 THEORY OF OPERATION 9-1 9.2 SYSTEM CONFIGURATION 9-2 9.3 SETTING UP THE EXTERNAL FIXED DISK DRIVE EXPANSION UNIT 9-6 Appendix A INDEX A-1
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xv FIGURES 5-1. Memory Error Locations on the 32-Bit System Memory Board 5-31 5-2. Memory Error Locations on the 1- to 2-Megabyte 32-Bit Memory Board 5-32 5-3. Memory Error Locations on the 4- to 8-Megabyte 32-Bit Memory Board 5-33 6-1. System Unit (Exterior and Battery) 6-11 6-2. System Unit (Interior with Memory Options) 6-13 6-3. System Unit (Interior with Controller Boards and Mass Storage Options) 6-15 6-4. COMPAQ Enhanced Keyboard 6-16 6-5. 84-Key Keyboard 6-17 6-6. COMPAQ Dual
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xvi 7-9. Removing the System Unit Cover 7-10 7-10. Overhead View of the COMPAQ DESKPRO 386 Personal Computer with the System Unit Cover Removed 7-11 7-11. Location of the Power Supply Assembly 7-12 7-12. Removing the Power Supply Screws 7-13 7-13. Removing the Power Supply Assembly 7-13 7-14. Location of the Power Supply Connector 7-14 on the System Board 7-15. Location of the Battery 7-16 7-16. Location of the Battery Connector 7-16 7-17. Removing the Battery 7-17 7-18. Removing
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xvii 7-30. Location of the Speaker/Board Guide Assembly 7-30 7-31. Removing the Speaker/Board Guide Assembly 7-30 7-32. Location of the Speaker Connector and Security Lock Switch Connector 7-31 7-33. Removing the Speaker Assembly 7-32 7-34. Removing the Security Lock Switch Assembly 7-32 7-35. Location Designators for COMPAQ DESKPRO 386 Mass Storage Devices 7-33 7-36. Location of the Cables for Mass Storage Devices in Positions A and D 7-34 7-37. Location of the Screws for Positions A a
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xviii 7-46. Removing the System Board 7-44 7-47. Removing the 80387 Coprocessor 7-46 7-48. Aligning the 80387 Coprocessor 7-47 8-1. COMPAQ DESKPRO 386 Personal Computer System Board Version 1 (assy. no. 000401) 8-2 8-2. COMPAQ DESKPRO 386 System Board Version 2 (assy. no. 000558) 8-4 8-3. 32-Bit System Memory Board (assy. no. 000413) 8-6 8-4. .5- to 2-Megabyte 16-Bit Memory Expansion Board (assy. no. 000458) 8-8 8-5a. 1- to 2-Megabyte 32-Bit Memory Expansion Board (assy. no. 000450)