Memory Problems - Lenovo ThinkServer TD200x Hardware Maintenance Manual

Memory problems

• Follow the suggested actions in the order in which they are listed in the Action column until the problem is
solved.
• See Chapter 8 "Parts Listing, TD200x Machine Types 3719, 3821, 3822, and 3823" on page 221 to determine
which components are customer replaceable units (CRU) and which components are field replaceable
units (FRU).
• 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:
• No error LEDs are lit on the operator information panel or on the DIMM.
• Memory mirroring does not account for the discrepancy.
• The memory modules are seated correctly.
• You have installed the correct type of memory.
• If you changed the memory, you updated the memory configuration in the
Setup utility.
• 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 for DIMM error messages:
• If a DIMM was disabled by a system-management interrupt (SMI), replace
the DIMM.
• If a DIMM was disabled by the user or by POST, run the Setup utility and
enable the DIMM.
3. Run memory diagnostics (see Running the diagnostic programs).
4. Make sure that there is no memory mismatch when the server is at the minimum
memory configuration (two 512 MB DIMMs; see the information about the
minimum required configuration on page Solving undetermined problems).
5. Add one pair of DIMMs at a time, making sure that the DIMMs in each pair
are matching.
6. Reseat the DIMMs.
7. Replace the components in step , one at a time, in the order shown, restarting
the server each time.
1. Reseat the DIMMs; then, restart the server.
2. Replace the lowest-numbered DIMMs with identical known good DIMMs;
then, restart the server. Repeat as necessary. If the failures continue after all
identified pairs are replaced, go to step.
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
you reinstall each DIMM. Replace the failed DIMM. Repeat step until you have
tested all removed DIMMs.
4. (Trained service technician only) Replace the system board.
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Chapter 5 Diagnostics