IBM Netfinity 4500R, Hardware Maintenance Manual

Page: 141 / 192

Symptom-to-FRU index
133
Bus fault messages
Undetermined problems
You are here because the diagnostic tests did not identify the failure, the Devices List
is incorrect, or the system is inoperative.
Note: A corrupt CMOS can cause undetermined problems.
Check the LEDs on all the power supplies, see“Power supply LED errors” on page
121. If the LEDs indicate the power supplies are working correctly, return here and do
the following:
1. Power-off the computer.
2. Be sure the system is cabled correctly.
3. Remove or disconnect the following (one at a time) until you find the failure
(power-on the computer and reconfigure each time).
Any external devices
Surge suppressor device (on the computer)
Modem, printer, mouse, or non-IBM devices
Each adapter
Drives
Memory-Modules (Minimum requirement = 128 MB (4x128 MB DIMMs))
Note:
Minimum operating requirements are:
a. 1 Power Supply
b. Power Backplane
c.
System Board
d. 1 Microprocessor and VRM
e.
1 Terminator Card
f. Memory Module (with a minimum of 1 bank of 128 MB DIMMs)
4. Power-on the computer. If the problem remains, suspect the following FRUs in
the order listed:
Power Supply
Power Backplane
Message Action
Failure reading 12C device.
Check devices on bus 0.
1. Replace system board
Failure reading 12C device.
Check devices on bus 1.
1. Reseat power Supply
2. Replace power supply
3. Replace power supply backplane
4. Replace system board
Failure reading 12C device.
Check devices on bus 2.
1. Replace DASD backplane
2. Replace system board
Failure reading 12C device.
Check devices on bus 3.
1. Replace system board
Failure reading 12C device.
Check devices on bus 4.
1. Replace DIMM
2. Replace system board