Dell OptiPlex GXa User manual

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Information in this document is subject to change without notice.
1996–1997 Dell Computer Corporation. All rights reserved.
Reproduction in any manner whatsoever without the written permission of Dell Computer Corporation is strictly forbidden.
Trademarks used in this text: Dell, the DELL logo, and OptiPlexare registered trademarks of Dell Computer Corporation; Intel and Pentium are registered trademarks
and MMX is a trademark of Intel Corporation; Microsoft, Windows, and MS-DOS are registered trademarks of Microsoft Corporation; IBM is a registered trademark
of International Business Machines Corporation; 3Com is a registered trademark of 3Com Corporation.
Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. Dell Computer
Corporation disclaims any proprietary interest in trademarks and trade names other than its own.
August 1997 P/N 51555

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Contents
Chapter 1
System Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Overview of Chassis Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Chassis Differences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Chassis Similarities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Standard Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Pentium II Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Secondary L2 Cache. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Main Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Upgradable BIOS in Flash Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
EIDE Subsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
SMART Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Built-In Diskette/Tape Drive Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Built-In SVGA Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Built-In Audio Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Built-In Ethernet NIC Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Network Cable Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Full Set of I/O Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Universal Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Location of Major Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Advanced Expansion Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Low-Profile Computer’s Expansion-Card Slots. . . . . . . . . . . . . . . . . . . . 1-9
Midsize Computer’s Expansion-Card Slots . . . . . . . . . . . . . . . . . . . . . . . 1-9
Mini Tower Computer’s Expansion-Card Slots . . . . . . . . . . . . . . . . . . . 1-10
Upgrade Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Microprocessor/L2 Cache Upgrades. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Main Memory Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Video-Memory Upgrade Option. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

vi
Computer Service Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
Online Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
System Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
System-Board Service Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
System Board Jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Interrupt Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
DMA Channel Assignments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Hard-Disk Drive Service Information . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
Hard-Disk Drive for the Low-Profile Computer . . . . . . . . . . . . . . . 1-18
Hard-Disk Drive for the Midsize Computer. . . . . . . . . . . . . . . . . . . 1-18
Hard-Disk Drive for the Mini Tower Computer . . . . . . . . . . . . . . . 1-18
Power-Supply Service Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
Pin Assignments for the DC Power Connectors . . . . . . . . . . . . . . . 1-20
DC Power Distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
Technical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Chapter 2
Basic Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Initial User Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
External Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Observing the Boot Routine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Internal Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Eliminating Resource Conflicts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Running the System Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Getting Help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Chapter 3
Beep Codes and Error Messages. . . . . . . . . . . . . . . . . . 3-1
POST Beep Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
System Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Chapter 4
Removing and Replacing Parts on the
Low-Profile Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Recommended Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Precautionary Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Inside the Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Computer Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

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Eject, Power, and Reset Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Front-Panel Inserts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
3.5-Inch Diskette Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
5.25-Inch Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Hard-Disk Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
System Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Expansion Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Expansion-Card Cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Expansion Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Riser Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
System Board Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
DIMMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Video Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
SEC Cartridge/Heat Sink Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
System Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21
Chapter 5
Removing and Replacing Parts on the
Midsize Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Recommended Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Precautionary Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Inside the Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Floor Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Computer Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Eject, Power, and Reset Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Front-Panel Inserts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Externally Accessible Drive Assemblies . . . . . . . . . . . . . . . . . . . . . . . . 5-10
3.5-Inch Diskette Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
5.25-Inch Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Hard-Disk Drive Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Hard-Disk Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
System Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14

viii
Expansion Cards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Expansion-Card Cage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Expansion Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Riser Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18
System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
DIMMs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Video Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Microprocessor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
SEC Cartridge/Heat Sink Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
System Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
Chapter 6
Removing and Replacing Parts on the
Mini Tower Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Recommended Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Precautionary Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Inside the Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Computer Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Front Bezel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Eject, Power, and Reset Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Front-Panel Inserts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Externally Accessible Drive Assemblies . . . . . . . . . . . . . . . . . . . . . . . . 6-10
3.5-Inch Diskette Drive Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
5.25-Inch Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Hard-Disk Drive Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Hard-Disk Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
System Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16
Expansion Cards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
Expansion-Card Cage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
Expansion Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Riser Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19
System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20

ix
System Board Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
DIMMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22
Video Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22
Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24
SEC Cartridge/Heat Sink Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24
System Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25
Appendix A
System Setup Program. . . . . . . . . . . . . . . . . . . . . . . . . . A-1
System Setup Screens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2
Index
Figures
Figure 1-1. Chassis Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Figure 1-2. Front-Panel Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Figure 1-3. Internal View of the Low-Profile Computer . . . . . . . . . . . . . . 1-7
Figure 1-4. Internal View of the Midsize Computer . . . . . . . . . . . . . . . . . 1-7
Figure 1-5. Internal View of the Mini Tower Computer . . . . . . . . . . . . . . 1-8
Figure 1-6. Riser Board for the Low-Profile Computer . . . . . . . . . . . . . . . 1-9
Figure 1-7. Riser Board for the Midsize Computer (Option 1) . . . . . . . . 1-10
Figure 1-8. Riser Board for the Midsize Computer (Option 2) . . . . . . . . 1-10
Figure 1-9. Riser Board for the Mini Tower Computer . . . . . . . . . . . . . . 1-11
Figure 1-10. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Figure 1-11. System Board Jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Figure 1-12. Computer Orientation Information . . . . . . . . . . . . . . . . . . . . 1-17
Figure 1-13. DC Power Connector P1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
Figure 1-14. DC Power Connectors P2 (Midsize and Mini Tower
Chassis); P3, P4, P5, P6, and P9 (All Chassis) . . . . . . . . . . . 1-20
Figure 1-15. DC Power Connectors P2 (Low-Profile Chassis) and
P7 (All Chassis) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
Figure 1-16. DC Power Cables for the Low-Profile Computer . . . . . . . . . 1-22
Figure 1-17. DC Power Distribution for the Low-Profile Computer . . . . . 1-23
Figure 1-18. DC Power Cables for the Midsize and
Mini Tower Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24
Figure 1-19. DC Power Distribution for the Midsize Computer . . . . . . . . 1-25
Figure 1-20. DC Power Distribution for the Mini Tower Computer . . . . . 1-26
Figure 4-1. Internal View of the Low-Profile Computer . . . . . . . . . . . . . . 4-3

x
Figure 4-2. Computer Cover Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Figure 4-3. Eject, Power, and Reset Button Removal . . . . . . . . . . . . . . . . 4-5
Figure 4-4. Front-Panel Insert Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Figure 4-5. Control Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Figure 4-6. Drive Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Figure 4-7. 3.5-Inch Diskette Drive Removal . . . . . . . . . . . . . . . . . . . . . . 4-9
Figure 4-8. 5.25-Inch Drive Assembly Removal. . . . . . . . . . . . . . . . . . . 4-10
Figure 4-9. Hard-Disk Drive Assembly Removal . . . . . . . . . . . . . . . . . . 4-11
Figure 4-10. System Power-Supply Removal . . . . . . . . . . . . . . . . . . . . . . 4-12
Figure 4-11. Expansion-Card Cage Removal . . . . . . . . . . . . . . . . . . . . . . 4-13
Figure 4-12. Expansion-Card Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Figure 4-13. Riser Board Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Figure 4-14. System Board Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Figure 4-15. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
Figure 4-16. DIMM Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Figure 4-17. DIMM Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Figure 4-18. Installing a Video-Memory Upgrade Module. . . . . . . . . . . . 4-19
Figure 4-19. SEC Cartridge/Heat Sink Removal . . . . . . . . . . . . . . . . . . . . 4-20
Figure 4-20. System Battery Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21
Figure 5-1. Internal View of the Midsize Computer . . . . . . . . . . . . . . . . . 5-3
Figure 5-2. Floor Stand Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Figure 5-3. Computer Cover Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Figure 5-4. Eject, Power, and Reset Button Removal . . . . . . . . . . . . . . . . 5-6
Figure 5-5. Front-Panel Insert Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Figure 5-6. Control Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Figure 5-7. Drive Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Figure 5-8. 3.5-Inch Diskette Drive Removal . . . . . . . . . . . . . . . . . . . . . 5-10
Figure 5-9. 5.25-Inch Drive Assembly Removal. . . . . . . . . . . . . . . . . . . 5-11
Figure 5-10. 5.25-Inch Drive Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Figure 5-11. Hard-Disk Drive Bracket Removal . . . . . . . . . . . . . . . . . . . . 5-12
Figure 5-12. Hard-Disk Drive Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
Figure 5-13. System Power-Supply Removal . . . . . . . . . . . . . . . . . . . . . . 5-14
Figure 5-14. Expansion-Card Cage Removal . . . . . . . . . . . . . . . . . . . . . . 5-15
Figure 5-15. Expansion-Card Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Figure 5-16. Riser Board Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
Figure 5-17. System Board Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18
Figure 5-18. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
Figure 5-19. DIMM Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20

xi
Figure 5-20. DIMM Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Figure 5-21. Installing a Video-Memory Upgrade Module . . . . . . . . . . . . 5-21
Figure 5-22. SEC Cartridge/Heat Sink Removal . . . . . . . . . . . . . . . . . . . . 5-22
Figure 5-23. System Battery Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
Figure 6-1. Internal View of the Mini Tower Computer . . . . . . . . . . . . . . 6-3
Figure 6-2. Computer Cover Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Figure 6-3. Front-Bezel Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Figure 6-4. Eject, Power, and Reset Button Removal . . . . . . . . . . . . . . . . 6-6
Figure 6-5. 5.25-Inch Front-Panel Insert Removal. . . . . . . . . . . . . . . . . . . 6-7
Figure 6-6. 3.5-Inch Front-Panel Insert Removal. . . . . . . . . . . . . . . . . . . . 6-8
Figure 6-7. Control Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Figure 6-8. Drive Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Figure 6-9. 3.5-Inch Diskette Drive Assembly Removal . . . . . . . . . . . . . 6-11
Figure 6-10. 3.5-Inch Diskette Drive Bracket . . . . . . . . . . . . . . . . . . . . . . 6-12
Figure 6-11. 5.25-Inch Drive Assembly Removal . . . . . . . . . . . . . . . . . . . 6-12
Figure 6-12. 5.25-Inch Drive Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13
Figure 6-13. Hard-Disk Drive Bracket Removal . . . . . . . . . . . . . . . . . . . . 6-14
Figure 6-14. Hard-Disk Drive Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
Figure 6-15. System Power-Supply Removal. . . . . . . . . . . . . . . . . . . . . . . 6-16
Figure 6-16. Expansion-Card Cage Removal. . . . . . . . . . . . . . . . . . . . . . . 6-17
Figure 6-17. Expansion-Card Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Figure 6-18. Riser Board Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19
Figure 6-19. System Board Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Figure 6-20. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
Figure 6-21. DIMM Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22
Figure 6-22. DIMM Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22
Figure 6-23. Installing a Video-Memory Upgrade Module . . . . . . . . . . . . 6-23
Figure 6-24. SEC Cartridge/Heat Sink Removal . . . . . . . . . . . . . . . . . . . . 6-24
Figure 6-25. System Battery Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25
Figure A-1. System Setup Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2

xii
Tables
Table 1-1. System-Board Jumper Descriptions . . . . . . . . . . . . . . . . . . . 1-15
Table 1-2. Interrupt Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
Table 1-3. DREQ Line Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Table 1-4. DC Voltage Ranges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
Table 1-5. Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Table 3-1. POST Beep Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Table 3-2. System Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Table A-1. System Setup Categories. . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3

xiii

R
ead This First
W
arnings, Cautions, and Notes
Throughout this manual, there may be blocks of text printed in bold type or in
italic type. These blocks are warnings, cautions, and notes, and they are used as
follows:
NOTE: A NOTE provides helpful information about using the computer system.
A prerequisite for using this manual to service Dell computer systems is a
basic knowledge of IBM®-compatible PCs and prior training in IBM-
compatible PC troubleshooting techniques. In addition to information
provided in this manual and the online System User’s Guide, Dell provides
the Diagnostics and Troubleshooting Guide for troubleshooting procedures
and instructions on using the Dell diagnostics to test the computer system.
WARNING: A WARNING indicates the potential for bodily harm and pro-
vides instructions for how to avoid the problem.
CAUTION: A CAUTION indicates either potential damage to hardware or
loss of data and provides instructions for how to avoid the problem.
xiv

System Overview 1-1
Chapter 1
System Overview
T
his manual contains field-servicing information for the Dell®OptiPlex®
GXa family of computers. The Dell OptiPlex GXa systems are high-speed
(233-, 266-, and 300-MHz), upgradable desktop computers built around the
high-performance Intel®Pentium®II microprocessors with MMXTM
technology.
Chapters 1 through 3 and Appendix A contain information that applies to all
models of the Dell OptiPlex GXa family; Chapters 4, 5, and 6 are chassis-
specific.
O
verview of Chassis Confi
g
urations
The Dell OptiPlex GXa systems are available in the following chassis
configurations:
•Low-profile desktop
•Midsize desktop
•Mini tower
Figure 1-1. Chassis Configurations
Midsize Chassis
Low-Profile Chassis
Mini Tower Chassis

1-2 Dell OptiPlex GXa Systems Service Manual
Chassis Differences
The three chassis configurations differ primarily in the following expansion
features:
•Number of expansion slots available for PCI/ISA expansion cards
•Number of available internal drive bays for EIDE/SCSI drives
•Number of available external drive bays for diskette, CD-ROM, or tape
drives
•Physical size and power supply types (the low-profile system contains a
smaller power supply than that used in the other two chassis configurations)
Due to the physical differences in the three chassis configurations, separate
parts removal and replacement chapters (Chapters 4 through 6) are provided for
each chassis type.
Chassis Similarities
All three chassis configurations have the following similarities:
•Identical system board
•Identical operational characteristics (same BIOS, POST, memory,
microprocessor, external I/O ports, and so on)
•Identical diagnostics, diagnostic beep codes, and diagnostic screen error
messages (see Chapters 1 through 3 and Appendix A).
S
tandard Features
The features described in the following subsections are common to all chassis
configurations.
Pentium II Microprocessor
All systems in the Dell OptiPlex GXa computer family incorporate the Pentium
II microprocessor for improved operating speeds and overall performance.
Some of the major enhancement features of the Pentium II microprocessor
include internal 16-KB data and instruction caches, internal math coprocessor,
and the MMX instruction set for high performance in complex multimedia and
communications environments. The Pentium II microprocessor also uses a tech-
nique called Single Instruction, Multiple Data (SIMD), which permits
processing data elements in parallel for additional system performance
enhancement.
The microprocessor is physically located in a single-edge contact (SEC)
cartridge/heat sink assembly on the system board for ease of upgrading when
faster processors are available. Contact Dell Computer Corporation for informa-
tion about Dell-supported microprocessor upgrades.

System Overview 1-3
Secondary L2 Cache
For additional performance, the Dell OptiPlex GXa systems employ a second-
ary cache memory subsystem with a cache memory controller and 512 KB of
pipeline-burst SRAM cache memory. The L2 cache SRAM is located in the
SEC cartridge/heat sink assembly on the system board.
Main Memory
Main memory for the Dell OptiPlex GXa systems range from a minimum of
16 MB of memory to a maximum of 324 MB. All main memory is implemented
using high-speed ECC and non-ECC DIMMs. One to three DIMMs ranging in
memory capacity sizes from 16 to 128 MB may be used to provide a maximum
memory capacity of 324 MB.
Upgradable BIOS in Flash Memory
The system BIOS is implemented in flash ROM, which allows for easy BIOS
upgrades using diskette files or downloaded files from Dell’s home page on the
World Wide Web. The BIOS also incorporates the POST diagnostics that test
the system each time the system is started.
EIDE Subsystem
The EIDE subsystem implemented on the system board provides two Mode-4,
DMA bus-mastered EIDE interfaces, each of which can support up to two EIDE
devices (for example, CD-ROM drive, hard-disk drive, and so on). The EIDE
controller attaches to the high-speed PCI local bus.
The primary EIDE interface (IDE1) provides support for up to two high-
performance EIDE devices. The computer’s boot drive should be connected to
the primary EIDE interface.
The secondary EIDE interface (IDE2) also provides support for up to two high-
performance EIDE devices, typically EIDE tape drives or CD-ROM drives.
NOTE: The externally accessible drive bays at the front of the computer are
normally used for diskette drives, CD-ROM drives, and/or tape drives.
Hard-disk drives should be installed in the internal hard-disk drive positions
described in “Hard-Disk Drive Service Information” found later in this chapter.
SMART Technology
As a standard feature, Dell OptiPlex GXa systems are equipped with Self-
Monitoring Analysis Reporting Technology (SMART), which warns you at
system start-up if your hard-disk drive has become unreliable. This warning
occurs only if you use hard-disk drives with SMART technology.
Built-In Diskette/Tape Drive Subsystem
The Dell OptiPlex GXa systems are equipped with an integrated diskette drive
controller (PC87307VUL) that can support a maximum of two non-EIDE dis-
kette and tape drives via a 34-pin DSKT connector located on the system board.

1-4 Dell OptiPlex GXa Systems Service Manual
The low-profile chassis can only accommodate one external drive device
(diskette drive or tape drive). Other chassis configurations can accommodate
two external drive devices.
NOTE: If the diskette drive and tape drive areboth attached to the diskette drive
controller on the system board, only the diskette drive is configured in the
System Setup program as Drive A or Drive B. The tape drive will then be listed
as Not Installed (under either the Drive A or Drive B category).
Built-In SVGA Subsystem
The Dell OptiPlex GXa systems include a built-in high-performance 64-bit
accelerated graphics port (AGP) subsystem, implemented on the system board,
which drives an external SVGA monitor. The AGP contains a dedicated bus
that bypasses the PCI bus and allows for interconnection of the video subsystem
directly to the Pentium chip set for extra high performance required for 3D
video subsystems. This architecture also off-loads the PCI bus providing greater
performance for devices attached to the PCI bus.
The maximum supported resolutions include 1600 x 1200 pixels with 256 col-
ors noninterlaced and 1024 x 768 pixels with 65,536 colors noninterlaced. The
SVGA subsystem consists of the following major components:
•ATI 3D Rage Pro SVGA video controller
•2-MB synchronous graphics random-access memory (SGRAM) video
memory (expandable to 4 MB via a video-memory upgrade kit)
•15-pin monitor port
Built-In Audio Controller
The built-in audio controller is a single chip that connects to the ISA bus. The
audio controller has analog jacks for line-in and microphone input. The single
line-out output jack provides stereo output for a line-level input to an external
amplifier or drives stereo headphones. See “Technical Specifications” found
later in this chapter for audio jack input and output specifications.
Built-In Ethernet NIC Support
The Dell OptiPlex GXa systems have an integrated 10/100-Mbps 3Com®PCI
3C905 Ethernet NIC subsystem. The subsystem supports both the 10BASE-T
and 100BASE-T standards. The NIC subsystem connects to the Ethernet net-
work through a single RJ45 connector on the back of the computer. The RJ45
connector and the NIC interface circuitry are mounted on the system board.
The NIC connector on the computer’s back panel has the following indicators:
•A yellow activity indicator flashes when the system is transmitting or
receiving network data. (A high volume of network traffic may make this
indicator appear to be in a steady “on” state.)
•A green link integrity indicator lights up when there is a good connection
between the network and the NIC. When the green indicator is off, the sys-
tem is not detecting a physical connection to the network.

System Overview 1-5
Network Cable Requirements
The computer’s NIC connector (RJ45) is designed for attaching to an
unshielded twisted pair (UTP) Ethernet cable. The other end of the cable con-
nects to an RJ45 jack wall plate or to an RJ45 port on a UTP concentrator or
hub, depending on the network configuration.
Chapter 4, “Using Integrated Devices,” in the Reference and Installation Guide
provides instructions for connecting the computer to, and configuring it for, use
on an Ethernet network.
Full Set of I/O Ports
For desktop connectivity, the Dell OptiPlex GXa systems include the following
ports:
•25-pin bidirectional parallel port with EPP/ECP and demand-mode DMA
support
•Two Universal Serial Bus (USB) ports
•Two 9-pin serial ports
•Two PS/2 ports (mouse and keyboard)
•One 15-pin monitor connector
•Three audio connectors (microphone jack, line-in jack, and line-out jack)
•One RJ45 Ethernet NIC connector
See Figures 1-3 through 1-5 for I/O port identifiers for the various chassis
configurations.
Universal Power Supply
The Dell OptiPlex GXa systems are equipped with a switch-selectable
(115/230 VAC) universal power supply that can operate from standard AC
power outlets in the U.S. and all international countries. The power supply used
in the midsize and mini tower chassis configurations is a higher capacity power
supply than that used in the low-profile chassis configuration. See additional
power supply information in “Technical Specifications” found later in this
chapter.

1-6 Dell OptiPlex GXa Systems Service Manual
Location of Major Components
Figure 1-2 shows the front-panel features for the three chassis configurations;
Figures 1-3 through 1-5 show internal features of the three chassis
configurations.
Figure 1-2. Front-Panel Features
diskette-drive
access indicator
reset button hard-disk drive
access indicator
power button power indicator
diskette-drive
access indicator
reset button hard-disk drive
access indicator
power button power indicator
Midsize Computer
Low-Profile Computer
Mini Tower Computer
power indicator
hard-disk drive
access indicator
power button
reset button

System Overview 1-7
Figure 1-3. Internal View of the Low-Profile Computer
Figure 1-4. Internal View of the Midsize Computer
serial port 1
connector
power supply
voltage
selection
switch
AC power
receptacle
3.5-inch diskette drive
expansion-card
cage
USB connectors (2)
keyboard connector
video connector
expansion-card slots (3)
hard-disk drive
serial port 2 connector
hard-disk drive
interface cable
diskette/tape drive
interface cable
audio connectors (3)
parallel port
connector
NIC connector
mouse connector
padlock ring
security cable
slot
parallel port
connector
power supply
voltage
selection switch
AC power
receptacle
serial port 1 connector
USB connectors (2)
keyboard connector
mouse connector
NIC connector
drive cage
diskette/tape drive interface cable hard-disk drive
bracket
hard-disk drive
interface cable
3.5-inch diskette drive
expansion-card cage
expansion-card slots (5)
audio connectors (3)
video connectorserial port 2 connector
security cable slot
padlock ring

1-8 Dell OptiPlex GXa Systems Service Manual
Figure 1-5. Internal View of the Mini Tower Computer
A
dvanced Expansion Features
The Dell OptiPlex GXa systems contain advanced expansion subsystems that
can support a mixture of traditional ISA expansion cards (called legacy cards),
Plug and Play ISA expansion cards, and PCI expansion cards.
For non-Plug and Play operating system environments, an ISA Configuration
Utility (ICU) included with the computer provides a means of avoiding
resource conflicts. Chapter 3, “Using the ISA Configuration Utility,” in the Ref-
erence and Installation Guide describes the ICU and provides instructions for
using it to configure the computer.
In the Microsoft®Windows®95 operating system, the functions provided by
the ICU are handled by the Device Manager, which can be accessed by double-
clicking the System icon in the Control Panel. See your Windows 95 documen-
tation for instructions on using the Device Manager to manage resources and
resolve conflicts.
power supply
security cable slot
serial port 2 connector
AC power receptacle
parallelportconnector
USB connectors
mouse connector
keyboard connector
serial port 1 connector
video connector
audio connectors (3)
padlock ring
system board
expansion-card
cage
riser board
hard-disk drive
bracket
external
drive bays
interface cable
NIC connector