IBM Type 7977 manual Memory problems, Symptom, Action

Memory problems

vFollow the suggested actions in the order in which they are listed in the Action column until the problem is solved.

vSee the Problem Determination and Service Guide on the IBM System x Documentation CD to determine which components are customer replaceable units (CRU) and which components are field replaceable units (FRU).

vIf 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
		v No error LEDs are lit on the operator information panel or on the DIMM.
amount of installed physical
		v Memory mirroring does not account for the discrepancy.
memory.
		v The memory modules are seated correctly.
		v You have installed the correct type of memory.
		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 system-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.	Make sure that there is no memory mismatch when the server is at the
		minimum memory configuration.
	4.	Add one pair of DIMMs at a time, making sure that the DIMMs in each pair are
		matching.
	5.	Reseat the DIMMs.
	6.	Replace the DIMMs, one at a time, restarting the server each time.
Multiple rows of DIMMs in a	1.	Reseat the DIMMs; then, restart the server.
branch are identified as failing.
	2.	Replace the lowest-numbered pair of DIMMs with an identical known good pair
		of DIMMs; then, restart the server. Repeat as necessary. If the failures continue
		after all identified pairs are replaced, go to 4.
	3.	Return the removed DIMMs, one pair at a time, to their original connectors,
		restarting the server after each pair, until 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.

Chapter 5. Solving problems 81