Memory Problems - IBM System x3610 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 7942 server," on page 37 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.
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IBM System x3610 Type 7942: Problem Determination and Service Guide
Action
1. Make sure that:
v No error LEDs are lit on the operator information panel.
v Memory reserved for the operating system does not account for the
discrepancy.
v The memory modules are seated correctly.
v You have installed the correct type of memory (see "Installing a memory
module" on page 52).
v All DIMMs are enabled. The server might have automatically disabled a
DIMM when it detected a problem. Use the BIOS Setup Utility program to
view and enable installed DIMMs.
2. Check the POST error log for memory error messages.
3. Run memory diagnostics (see "Running the diagnostic programs" on page 105).
4. Remove the DIMMs; then, add one DIMM or pair of DIMMs at a time, making
sure that the DIMMs in each pair are matching. Install the DIMMs in the
sequence that is described in "Installing a memory module" on page 52.
5. Reseat the DIMMs.
6. Replace the following components one at a time, in the order shown, restarting
the server each time:
a. DIMMs (make sure to enable the DIMMs after installation: Advanced –>
Memory settings in the BIOS Setup Utility)
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. Enable all the DIMMs (Advanced –> Memory settings in the BIOS Setup
Utility).
4. (Trained service technician only) Replace the system board.