Lenovo ThinkSystem SR645 Maintenance Manual page 258

• No DIMM error LEDs are lit on the system board.
• Memory mirrored channel 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.
• There is no memory mismatch when the server is at the minimum memory configuration.
2. Reseat the DIMMs and then restart the server.
3. Run the memory module diagnostics. When you start a server and press F1, the Lenovo XClarity
Provisioning Manager V3 interface is displayed by default. You can perform memory diagnostics from
this interface. From the Diagnostic page, click Run Diagnostic ➙ Memory test.
4. Check the POST error log:
• If a DIMM was disabled by a systems-management interrupt (SMI), replace the DIMM.
• If a DIMM was disabled by the user or by POST, reseat the DIMM; then, run the Setup utility and
enable the DIMM.
5. Reseat the DIMM.
6. Restart the server.
Multiple rows of DIMMs in a branch 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
known good DIMM; then, restart the server. Repeat as necessary. If the failures continue after all
identified DIMMs are replaced, go to step 4.
3. Return the removed DIMMs, one at a time, to their original connectors, restarting the server after each
DIMM, until a DIMM fails. Replace each failing DIMM with an identical known good DIMM, restarting the
server after each DIMM replacement. Repeat step 3 until you have tested all removed DIMMs.
4. Replace the lowest-numbered DIMM of those identified; then, restart the server. Repeat as necessary.
5. Reverse the DIMMs between the channels (of the same processor), and then restart the server. If the
problem is related to a DIMM, replace the failing DIMM.
6. Swap processors to see if the memory issue followed by the processors or DIMMs. If it follows the failing
components, then replace the failing components.
7. (Trained technician only) Replace the system board.
DIMM PFA issue
1. Update the UEFI and XCC firmware to the latest version.
2. Reseat the failing DIMMs.
3. Swap processors and make sure that there are no damages to processor socket pins.
4. (Train service only) Ensure there is no abnormal material in any DIMM slot.
5. Run the memory module diagnostics. When you start a server and press F1, the Lenovo XClarity
Provisioning Manager V3 interface is displayed by default. You can perform memory diagnostics from
this interface. From the Diagnostic page, click Run Diagnostic ➙ Memory test.
6. Replace the failing DIMMs that fails Memory Test.
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