Apple Mac Pro (Memory DIMMs Replacement) - Manual (Page 10)

073-1246 Rev. B 10 © 2009 Apple Inc. All rights reserved.
How to
Troubleshoot
Memory LEDs
Follow this procedure when troubleshooting each DIMM identified by a red LED:
Remove and reseat DIMM. 1.
Restart computer. If associated LED is no longer illuminated, issue is resolved. 2.
If associated LED remains illuminated, replace DIMM with new DIMM. 3.
Restart computer and verify LED is no longer illuminated. 4.
There is one exception. If two LEDs illuminate at the same time for the 3 DIMM and 4 DIMM
slots or for the 7 DIMM and 8 DIMM slots, check both DIMMs using this process:
Check Result Action
Remove both DIMMs identified by 1.
illuminated LEDs. Set DIMM 4 (or
DIMM 8) aside, and reseat DIMM 3 (or
DIMM 7). Restart computer. Is DIMM 3
(or DIMM 7) LED illuminated?
Yes Replace DIMM 3 (or DIMM 7) with
new DIMM. Go to step 2.
No Go to step 2.
Reinstall DIMM 4 (or DIMM 8). Restart 2.
computer. Is one or both LEDs
illuminated?
Yes Replace DIMM 4 (or DIMM 8) with
new DIMM.
No Issue resolved.
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