IBM 84885BU, Maintenance And Troubleshooting Manual

Page: 137 / 200

Undetermined problems
Use the information in this section if the diagnostic tests did not identify the failure,
the devices list is incorrect, or the system is inoperative.
Damaged data in CMOS memory or damaged BIOS code can cause undetermined
problems. To reset the CMOS data, use the CMOS recovery jumper to override the
power-on password and clear the CMOS memory; see “Erasing a lost or forgotten
password (clearing CMOS)” on page 19. If you suspect that the BIOS code is
damaged, see “Recovering from a POST/BIOS update failure” on page 18.
Check the LEDs on all the power supplies. If the LEDs indicate the power supplies
are working correctly, complete the following steps:
1. Turn off the server.
2. Be sure the server is cabled correctly.
3. Remove or disconnect the following devices (one at a time) until you find the
failure (turn on the server and reconfigure each time):
v
Any external devices
v
Surge suppressor device (on the server)
v Modem, printer, mouse, or non-IBM devices
v Each adapter
v Drives
v Memory modules (minimum requirement = 512 MB (2 banks of 256 MB
DIMMs))
Note: Minimum operating requirements are:
a. One power supply
b. Power cage assembly, if installed
c. System board
d. One microprocessor
e. Memory module (with a minimum of two 256 MB DIMMs)
4. Turn on the server. If the problem remains, suspect the following FRUs in the
order listed:
v
Power supply
v
Power cage assembly, if installed
v
System board
Notes:
1. If the problem goes away when you remove an adapter from the system and
replacing that adapter does not correct the problem, suspect the system board.
2. If you suspect a networking problem and all the system tests pass, suspect a
network cabling problem external to the system.
Chapter 6. Symptom-to-FRU index
127