Memory Problems - IBM System x3550 Type 7978 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, Type 7978 and 1913 server," on page 89 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.
Action
1. Make sure that:
v No light path diagnostics LEDs are lit on the operator information panel.
v Memory mirroring or sparing does not account for the discrepancy.
v The DIMMs are seated correctly.
v You have installed the correct type of memory. See "Installing a memory
module" on page 110.
v If you changed the memory, you updated the memory configuration in the
Configuration/Setup Utility program.
v All banks of memory are enabled. The server might have automatically
disabled a memory bank when it detected a problem, or a memory bank
might have been manually disabled.
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.
v If a DIMM was disabled by the user or by POST, run the Configuration/Setup
Utility program and enable the DIMM.
3. Run memory diagnostics (see "Running the diagnostic programs" on page 62).
4. Add one pair of DIMMs at a time, making sure that the DIMMs in each pair are
matching. Install the DIMMs in the sequence described in "Installing a memory
module" on page 110.
5. Reseat the DIMMs. See "Installing a memory module" on page 110.
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. If the DIMM was disabled the user or POST, run the Configuration/Setup Utility
program and enable the DIMM.
3. Replace the lowest-numbered DIMM pair of those identified; then, restart the
server. Repeat as necessary.
4. (Trained service technician only) Replace the system board.
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Chapter 2. Diagnostics