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 DELLlogo, and OptiPlex are registered trademarks of Dell Computer Corporation; Inteland 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.
November 1997 P/N 51555 Rev. A01

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Contents
Chapter 1
System Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Chassis Differences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Chassis Similarities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Standard Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Pentium II Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Secondary L2 Cache. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Main Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Upgradable BIOS in Flash Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
EIDE Subsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
SMART Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Built-In Diskette/Tape Drive Controller. . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Built-In SVGA Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Built-In Audio Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Built-In Ethernet NIC Support (Optional on EM System Board) . . . . . . 1-5
Network Cable Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Full Set of I/O Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Universal Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Location of Major Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Advanced Expansion Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
OptiPlex NX Computer’s Expansion-Card Slot. . . . . . . . . . . . . . . . . . . 1-12
Low-Profile Computer’s Expansion-Card Slots. . . . . . . . . . . . . . . . . . . 1-12
Midsize Computer’s Expansion-Card Slots . . . . . . . . . . . . . . . . . . . . . . 1-13
Mini Tower Computer’s Expansion-Card Slots . . . . . . . . . . . . . . . . . . . 1-14
Upgrade Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Microprocessor/L2 Cache Upgrades. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Main Memory Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Video-Memory Upgrade Option. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

vi
Computer Service Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
Remote Management Support Features (Optional) . . . . . . . . . . . . . . . . 1-16
Online Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
System Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
System-Board Service Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
System Board Jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
Interrupt Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
DMA Channel Assignments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
Hard-Disk Drive Service Information . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22
Hard-Disk Drive for the Net PC Computer . . . . . . . . . . . . . . . . . . . 1-22
Hard-Disk Drive for the Low-Profile Computer . . . . . . . . . . . . . . . 1-23
Hard-Disk Drive for the Midsize Computer. . . . . . . . . . . . . . . . . . . 1-23
Hard-Disk Drive for the Mini Tower Computer . . . . . . . . . . . . . . . 1-23
Power-Supply Service Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
Pin Assignments for the DC Power Connectors . . . . . . . . . . . . . . . 1-25
DC Power Distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
OptiPlex NX Computer Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . 1-32
OptiPlex NX Pin Assignments for the DC Power Connectors . . . . 1-33
DC Power Distribution for the OptiPlex NX . . . . . . . . . . . . . . . . . . 1-34
Technical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36
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 Computer Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Server-Based Diagnostics (EM System Board Only) . . . . . . . . . . . . . . . 2-6
Hard-Disk–Based Diagnostics (Net PC Systems Only). . . . . . . . . . . . . . 2-7
Diskette-Based Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Connecting an External Diskette Drive to the NX Computer . . . . . . 2-9
Running the Diskette-Based Diagnostics. . . . . . . . . . . . . . . . . . . . . 2-10
Getting Help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

vii
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
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

viii
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
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

ix
Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Externally Accessible Drive Assemblies . . . . . . . . . . . . . . . . . . . . . . . . 6-10
3.5-Inch Diskette Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
5.25-Inch Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13
Hard-Disk Drive Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
Hard-Disk Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16
System Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
Expansion Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Expansion-Card Cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Expansion Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19
Riser Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20
System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
System Board Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22
DIMMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23
Video Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23
Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25
SEC Cartridge/Heat Sink Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25
System Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26
Chapter 7
Removing and Replacing Parts
on the Net PC Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Recommended Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Precautionary Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Stand for Vertical Orientation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Computer Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Hard-Disk Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
System Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
System Board Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Expansion-Card Cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Expansion Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
Riser Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11
DIMMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12
Video Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12
Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14
SEC Cartridge/Heat Sink Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14

x
System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15
System Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16
Appendix A
System Setup Program . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
System Setup Screens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2
Index
Figures
Figure 1-1. Chassis Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Figure 1-2. Front-Panel Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Figure 1-3. Internal View of the Low-Profile Chassis. . . . . . . . . . . . . . . . 1-9
Figure 1-4. Internal View of the Midsize Chassis . . . . . . . . . . . . . . . . . . . 1-9
Figure 1-5. Internal View of the Mini Tower Chassis . . . . . . . . . . . . . . . 1-10
Figure 1-6. Internal View of the Net PC Chassis. . . . . . . . . . . . . . . . . . . 1-11
Figure 1-7. Riser Board for Net PC Computer. . . . . . . . . . . . . . . . . . . . . 1-12
Figure 1-8. Riser Board for the Low-Profile Computer. . . . . . . . . . . . . . 1-12
Figure 1-9. EM Riser Board for the Low-Profile Computer . . . . . . . . . . 1-13
Figure 1-10. Riser Board for the Midsize Computer (Option 1) . . . . . . . . 1-13
Figure 1-11. Riser Board for the Midsize Computer (Option 2) . . . . . . . . 1-14
Figure 1-12. EM Riser Board for the Midsize Computer . . . . . . . . . . . . . 1-14
Figure 1-13. Riser Board for the Mini Tower Computer. . . . . . . . . . . . . . 1-15
Figure 1-14. EM Riser Board for the Mini Tower Computer . . . . . . . . . . 1-15
Figure 1-15. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
Figure 1-16. System Board Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
Figure 1-17. Computer Orientation Information . . . . . . . . . . . . . . . . . . . . 1-22
Figure 1-18. DC Power Connector P1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
Figure 1-19. DC Power Connectors P2 (Midsize and Mini Tower Chassis);
P3, P4, P5, P6, and P9 (All OptiPlex GXa Chassis) . . . . . . . 1-25
Figure 1-20. DC Power Connectors P2 (Low-Profile Chassis) and P7
(All OptiPlex GXa Chassis) . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
Figure 1-21. DC Power Cables for the Low-Profile Computer . . . . . . . . . 1-27
Figure 1-22. DC Power Distribution for the Low-Profile Computer. . . . . 1-28
Figure 1-23. DC Power Cables for the Midsize and
Mini Tower Computers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-29
Figure 1-24. DC Power Distribution for the Midsize Computer . . . . . . . . 1-30
Figure 1-25. DC Power Distribution for the Mini Tower Computer . . . . . 1-31

xi
Figure 1-26. DC Power Connector P1 for the OptiPlex NX . . . . . . . . . . . 1-33
Figure 1-27. DC Power Connector P2 for the OptiPlex NX . . . . . . . . . . . 1-33
Figure 1-28. DC Power Connector P3 for the OptiPlex NX . . . . . . . . . . . 1-34
Figure 1-29. DC Power Cables for the OptiPlex NX Computer . . . . . . . . 1-34
Figure 1-30. DC Power Distribution for the OptiPlex NX Computer . . . . 1-35
Figure 2-1. Connecting an External Diskette Drive
to the NX Computer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Figure 4-1. Internal View of the Low-Profile Computer . . . . . . . . . . . . . . 4-3
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

xii
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
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. . . . . . . . . . . . . . . . . . . 6-13
Figure 6-12. 5.25-Inch Drive Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Figure 6-13. Hard-Disk Drive Bracket Removal . . . . . . . . . . . . . . . . . . . . 6-15
Figure 6-14. Hard-Disk Drive Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16
Figure 6-15. System Power-Supply Removal . . . . . . . . . . . . . . . . . . . . . . 6-17
Figure 6-16. Expansion-Card Cage Removal . . . . . . . . . . . . . . . . . . . . . . 6-18
Figure 6-17. Expansion-Card Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19
Figure 6-18. Riser Board Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Figure 6-19. System Board Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
Figure 6-20. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . 6-22
Figure 6-21. DIMM Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23
Figure 6-22. DIMM Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23
Figure 6-23. Installing a Video-Memory Upgrade Module. . . . . . . . . . . . 6-24
Figure 6-24. SEC Cartridge/Heat Sink Removal . . . . . . . . . . . . . . . . . . . . 6-25
Figure 6-25. System Battery Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26
Figure 7-1. Optional Stand Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Figure 7-2. Computer Cover Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

xiii
Figure 7-3. Service Access Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Figure 7-4. Control Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5
Figure 7-5. Hard-Disk Drive Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Figure 7-6. System Power-Supply Removal. . . . . . . . . . . . . . . . . . . . . . . . 7-7
Figure 7-7. System Board Components . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Figure 7-8. Expansion-Card Cage Removal. . . . . . . . . . . . . . . . . . . . . . . . 7-9
Figure 7-9. Expansion-Card Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
Figure 7-10. Riser Board Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11
Figure 7-11. DIMM Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12
Figure 7-12. DIMM Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12
Figure 7-13. Installing a Video-Memory Upgrade Module . . . . . . . . . . . . 7-13
Figure 7-14. SEC Cartridge/Heat Sink Removal . . . . . . . . . . . . . . . . . . . . 7-14
Figure 7-15. System Board Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15
Figure 7-16. System Battery Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16
Figure A-1. System Setup Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2
Tables
Table 1-1. System-Board Jumper Descriptions. . . . . . . . . . . . . . . . . . . . 1-20
Table 1-2. Interrupt Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
Table 1-3. DREQ Line Assignments. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
Table 1-4. OptiPlex GXa DC Voltage Ranges . . . . . . . . . . . . . . . . . . . . 1-24
Table 1-5. OptiPlex NX DC Voltage Ranges . . . . . . . . . . . . . . . . . . . . . 1-32
Table 1-6. Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36
Table 3-1. POST Beep Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Table 3-2. System Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Table A-1. System Setup Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3

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
provides 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 and Optiplex NX family of computers. The Dell OptiPlex GXa and
OptiPlex NX systems are high-speed (233-, 266-, and 300-MHz), upgradable
desktop computers built around high-performance Intel®Pentium®II
microprocessors with MMXTM technology.
The OptiPlex GXa systems use either a standard system board with integrated
NIC controller or an enhanced manageability (EM) system board with optional
NIC controller and support for an optional Network Interface Card with Wake-
up On LAN capability. All OptiPlex NX systems use the EM system board.
Enhanced manageability systems are identified by the phrase “Enhanced Man-
ageability,” which is printed on the computer’s FCC label and also displayed in
the boot banner when the computer is powered up.
The OptiPlex GXa systems are available in three different chassis configura-
tions: low-profile desktop, midsize desktop, and mini tower (see Figure 1-1).
The OptiPlex NX computer is available only in the Net PC chassis (see
Figure 1-1).
Chapters 1 through 3 and Appendix A contain information that applies to all
models of the OptiPlex GXa and OptiPlex NX families; Chapters 4, 5, 6, and 7
are chassis-specific.

1-2 Dell OptiPlex GXa and OptiPlex NX Systems Service Manual
Figure 1-1. Chassis Configurations
C
hassis Differences
The three OptiPlex GXa and the OptiPlex Net PC 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 midsize and mini tower systems
use the same power supply)
NOTE: Computers with Enhanced Manageability support contain a different
system board, riser board and a power supply with a secondary winding that
provides trickle (“flea”) power for the Wakeup On LAN feature when computer
power is turned off.
Due to the physical differences in the four chassis configurations, a separate
parts removal and replacement chapter (Chapters 4 through 7) is provided for
each chassis type.
Midsize Chassis
Low-Profile Chassis
Mini Tower Chassis
Net PC C
hassis

System Overview 1-3
C
hassis Similarities
All four chassis configurations have the following similarities:
•Use the same system board (OptiPlex GXa systems can use either the stan-
dard or EM system board; the OptiPlex NX systems use the EM 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). However, the
OptiPlex NX computer has no built-in diskette drive and requires a special
setup to run diskette-based diagnostics as described in Chapter 2.
S
tandard Features
The features described in the following subsections are common to all chassis
configurations. However, some of the features differ slightly, depending on
which version of the system board is installed (standard or enhanced manage-
ability version). Where differences occur, they are marked in the paragraph
titles.
Pentium II Microprocessor
All systems in the OptiPlex GXa and OptiPlex NX computer families incorpo-
rate the Pentium II microprocessor for improved operating speeds and overall
performance. Some of the major enhancement features of the Pentium II micro-
processor 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 technique 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.
Secondary L2 Cache
For additional performance, the OptiPlex GXa and OptiPlex NX systems
employ a secondary 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.

1-4 Dell OptiPlex GXa and OptiPlex NX Systems Service Manual
Main Memory
Main memory for the OptiPlex GXa and OptiPlex NX systems ranges from a
minimum of 16 MB to a maximum of 384 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 384 MB.
Upgradable BIOS in Flash Memory
The system BIOS is implemented in flash ROM, which allows for easy BIOS
upgrades using diskette files or files downloaded from Dell’s home page on the
World Wide Web (www.dell.com). The BIOS also incorporates the POST diag-
nostics 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.
NOTES: Any 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.
The OptiPlex NX system supports only one hard-disk drive and optionally one
external diskette drive for running diskette-based diagnostics as described in
Chapter 2,“Basic Troubleshooting”.
SMART Technology
As a standard feature, OptiPlex GXa and OptiPlex NX 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 warn-
ing occurs only if you use hard-disk drives with SMART technology.
Built-In Diskette/Tape Drive Controller
The OptiPlex GXa and OptiPlex NX systems are equipped with an integrated
diskette drive controller (PC87307VUL) that can support a maximum of two
non-EIDE diskette and tape drives via a 34-pin DSKT connector located on the
system board. The low-profile chassis can accommodate only one external drive
device (diskette drive or tape drive). Other chassis configurations can accom-
modate two external drive devices.

System Overview 1-5
NOTES: If the diskette drive and tape drive are both 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).
The OptiPlex NX system contains an integrated controller and diskette-drive
connector but is not equipped with a diskette drive. If you run diskette-based
diagnostics, this computer requires an external diskette drive kit as described in
Chapter 2.
Built-In SVGA Subsystem
The OptiPlex GXa and OptiPlex NX 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 con-
tains a dedicated bus that bypasses the PCI bus and allows for interconnection
of the video subsystem directly to the Pentium chip set for the extra high perfor-
mance 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-hole 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 (Optional on EM System
Board)
The OptiPlex GXa systems and Optiplex NX systems are available with or
without the built-in Ethernet NIC subsystem (optional if using the EM system
board).
The standard integrated 3Com 3C905 NIC does not support the Wakeup On
LAN feature. Wakeup On LAN capability can be provided by an optional
expansion card with a +5-VFP cable that connects to the P1 connector on the
EM riser board.
The integrated 10/100-Mbps 3Com®PCI 3C905 Ethernet NIC subsystem sup-
ports both the 10BASE-T and 100BASE-T standards. The NIC subsystem
connects to the Ethernet network through a single RJ45 connector on the back

1-6 Dell OptiPlex GXa and OptiPlex NX Systems Service Manual
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.
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. For OptiPlex NX systems, refer to the online Network
Administrator’s Guide.
Full Set of I/O Ports
For desktop connectivity, the OptiPlex GXa and OptiPlex NX systems include
the following ports:
•25-hole, 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-hole video connector
•Three audio jacks (microphone, line-in, and line-out)
•One RJ45 Ethernet NIC connector
See Figures 1-3 through 1-5 for I/O port identifiers for the various chassis
configurations.

System Overview 1-7
Universal Power Supply
The OptiPlex GXa and OptiPlex NX 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 and NX chassis
configurations.
Dell OptiPlex GXa systems equipped with the EM system board and all
OptiPlex NX systems have a special power supply that provides trickle (“flea”)
power to support the Wakeup On LAN feature when computer power is off.
Location of Major Components
Figure 1-2 shows the front-panel features for the four chassis types; Figures 1-3
through 1-5 show internal features of the four chassis types.

1-8 Dell OptiPlex GXa and OptiPlex NX Systems Service Manual
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 Chassis
Low-Profile Chassis
power indicator
hard-disk drive
access indicator
power button
reset button
Mini Tower Chassis
Net PC Chassis
hard-disk drive
access indicator
power button
power indicator