Memory Problems - IBM x3400 7975 Problem Determination And Service Manual

Memory problems

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, System x3400 Types 7973, 7974, 7975 and 7976," on page 87 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.
Symptom
The amount of system memory
that is displayed is less than the
amount of installed physical
memory.
Multiple rows of DIMMs in a
branch are identified as failing.
46
System x3400 Types 7973, 7974, 7975, and 7976: Problem Determination and Service Guide
Action
1. Make sure that:
v No error LEDs are lit on the control-panel assembly or on the system board.
v Memory mirroring does not account for the discrepancy.
v The memory modules are seated correctly.
v You have installed the correct type of memory.
v All DIMMs are enabled. The server might have automatically disabled a
DIMM when it detected a problem.
2. Check the POST error log for error message 289:
v If a DIMM was disabled by a system-management interrupt (SMI), replace
the DIMM.
3. Run memory diagnostics (see "Running the diagnostic programs" on page 58).
4. Make sure that there is no memory mismatch when the server is over the
minimum memory configuration (one 512 MB DIMM) and that you have
installed the correct number of DIMMs (see the User's Guide on the IBM
System x3400 Documentation CD for information about installing memory
modules).
5. Reseat the DIMMs.
6. Replace the following components one at a time, in the order shown, restarting
the server each time:
a. DIMMs
b. (Trained service technician only) System board
1. Reseat the DIMMs; then, restart the server.
2. Replace the lowest-numbered DIMM pair of those that are identified; then,
restart the server. Repeat as necessary.
3. (Trained service technician only) Replace the system board.