Compaq AlphaServer DS20 Service Manual page 4

Chapter 3 Error Registers
3.1 Ibox Status Register - I_STAT..................................................................3-2
3.2 Memory Management Status Register - MM_STAT.................................3-3
3.3 Dcache Status Register - DC_STAT.........................................................3-5
3.4 Cbox Read Register..................................................................................3-7
3.5 Miscellaneous Register (MISC) ................................................................3-9
3.6 Device Interrupt Request Register (DIRn, n=0,1) .................................... 3-12
3.7 Pchip Error Register (PERROR).............................................................3-13
3.8 Failure Register ......................................................................................3-16
3.9 Function Register ................................................................................... 3-18
Chapter 4 Removal and Replacement
4.1 System Safety ..........................................................................................4-1
4.2 FRU List ..................................................................................................4-2
4.3 System Access .........................................................................................4-6
4.4 CPU Removal and Replacement ...............................................................4-8
4.5 Memory Module Removal and
4.6 System Board Removal and Replacement ............................................... 4-12
4.7 PCI/ISA Option Removal and Replacement ............................................ 4-14
4.8 Server Feature Module Removal and Replacement.................................. 4-16
4.9 Power Supply Removal and Replacement ............................................... 4-18
4.10 Power Harness Removal and Replacement.............................................. 4-20
4.11 Power Transition Module Removal and Replacement.............................. 4-22
4.12 Auxiliary Fan Removal and Replacement ............................................... 4-24
4.13 System Fan Removal and Replacement................................................... 4-26
4.14 Cover Interlock Removal and Replacement............................................. 4-28
4.15 Operator Control Panel Removal and Replacement ................................ 4-30
4.16 CD-ROM Removal and Replacement .....................................................4-32
4.17 Floppy Removal and Replacement.......................................................... 4-34
4.18 SCSI Disk Removal and Replacement .................................................... 4-36
4.19 StorageWorks Backplane Removal and Replacement .............................. 4-38
4.20 StorageWorks UltraSCSI Bus Extender Removal and Replacement......... 4-40
Appendix A Halts, Console Commands, and Environment
Variables
A.1 Halt Button Functions.............................................................................. A-2
A.2 Using the Halt Button.............................................................................. A-3
A.3 Halt Assertion ......................................................................................... A-4
A.4 Summary of SRM Console Commands .................................................... A-6
A.5 Summary of SRM Environment Variables ............................................... A-8
A.6 Recording Environment Variables ......................................................... A-10
iv
Replacement ..................................4-10