IBM x3655 Service Guide - Page 148

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 x3655, Type 7985," on page 97 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 1. Make sure that: that is displayed is less than the amount of installed physical v No error LEDs are lit on the operator information panel. memory. v Memory sparing 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 62). 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 systems-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 144). 4. Make sure that there is no memory mismatch when the server is at the minimum memory configuration (two 512 MB DIMMs). 5. Add one pair of DIMMs at a time, making sure that the DIMMs in each pair match. Install the DIMMs in the sequence described in "Installing a memory module" on page 62. 6. Reseat the DIMMs. 7. 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 Multiple rows of DIMMs in a failing 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. (Trained service technician only) Replace the system board. 130 IBM System x3655 Type 7985: Problem Determination and Service Guide