IBM System x3690 X5, Service Manual, Page: 75 / 464

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 4, “Parts listing, System x3690 X5 Types 7147, 7148, 7149, and 7192,” on page 249 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 Action
The amount of system memory
that is displayed is less than the
amount of installed physical
memory. Note: If you change memory, you must update the memory configuration in the
Setup utility.
1. Make sure that:
v No error LEDs are lit on the operator information panel, on the memory
tray, or on the MAX5 memory expansion module.
v
Memory mirroring does not account for the discrepancy.
v
The memory modules are seated correctly (see “Removing a memory
module” on page 295 and “Replacing a memory module” on page 296).
v
You have installed the correct type of memory.
v
If you changed the memory, you updated the memory configuration in the
Setup utility.
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 event log:
v If a DIMM was disabled by a systems-management interrupt (SMI), replace
the DIMM.
v
If a DIMM was disabled by the user or by POST, run the Setup utility and
enable the DIMM.
3.
Run memory diagnostics (see “IBM Dynamic System Analysis” on page 80).
4.
Make sure that there is no memory mismatch when the server is at the
minimum memory configuration ( see “Replacing a memory module” on page
296 for information about DIMM rules and population sequence).
5. For the system board, memory tray, and the MAX5 memory expansion
module, add one pair of DIMMs at a time, making sure that the DIMMs in
each pair match ( see “Replacing a memory module” on page 296 and
“Replacing a MAX5 memory module” on page 384).
6. Reseat the DIMM.
7. Restart the server.
Multiple rows of DIMMs in a
branch are identified as failing.
1. Reseat the DIMMs; then, restart the server.
2. Remove the lowest-numbered DIMM pair of those that are identified and
replace it with an identical pair of known good DIMMs; then, restart the
server. Repeat as necessary. If the failures continue after all identified pairs are
replaced, go to step 4.
3. Return the removed DIMMs, one pair at a time, to their original connectors,
restarting the server after each pair, until a pair fails. Replace each DIMM in
the failed pair with an identical known good DIMM, restarting the server after
each DIMM. Replace the failed DIMM. Repeat step 3 until you have tested all
removed DIMMs.
4. Replace the lowest-numbered DIMM pair of those identified; then, restart the
server. Repeat as necessary.
5.
(Trained service technician only) Replace the system board.
Chapter 3. Diagnostics
57