IBM x3950 Problem Determination And Service Manual page 98

v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 3, "Parts listing, Type 8878 and 8879," on page 109 to determine which components are
customer replaceable units (CRU) and which components are field replaceable units (FRU).
v If an action step is preceded by "(Trained service technician only)," that step must be performed only by a
trained service technician.
System-error log message
12V B Bus Fault
12V C Bus Fault
12V D Bus Fault
12V E Bus Fault
12V Planar Fault
12V Power Good Fault
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IBM System x3950 Type 8878 and System x3950 E Type 8879: Problem Determination and Service Guide
Action
1. Reseat the following components:
a. Disk drives
b. SAS hard disk drive backplane cables
2. Replace the following components one at a time, in the order
shown, restarting the server each time:
a. Disk drives
b. SAS hard disk drive backplane
c. (Trained service technician only) Power backplane
d. (Trained service technician only) PCI-X board
1. Reseat the following components:
a. Adapters
b. Microprocessor tray
2. Replace the following components one at a time, in the order
shown, restarting the server each time:
a. Adapters
b. (Trained service technician only) PCI-X board
c. (Trained service technician only) Power backplane
1. Reseat the following components:
a. Microprocessor tray
b. Memory cards 3 and 4
2. Replace the following components one at a time, in the order
shown, restarting the server each time:
a. Memory cards 3 and 4
b. (Trained service technician only) Power backplane
c. (Trained service technician only) Microprocessor tray
1. Reseat the following components:
a. Microprocessor tray
b. Memory cards 1 and 2
2. Replace the following components one at a time, in the order
shown, restarting the server each time:
a. Memory cards 1 and 2
b. (Trained service technician only) Power backplane
c. (Trained service technician only) Microprocessor tray
1. Reseat the microprocessor tray.
2. Replace the power backplane.
1. Reseat the microprocessor tray.
2. Reseat the memory cards.
3. (Trained service technician only) Replace the power backplane.
4. (Trained service technician only) Replace the microprocessor
tray.