Apple Workgroup Server 9150 - Manual (Page 52)

Troubleshooting Symptom Charts/Miscellaneous
(Continued)
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Miscellaneous
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About This Macintosh
reports less memory
than is installed
1 Verify that RAM SIMMs are installed in matching pairs
(same size and speed).
2 Replace RAM SIMMs.
System hangs, I/O
errors, or “mirrors
out of sync” errors
resulting from SCSI
Bus-intensive
activity
1 Verify that system software is version 7.1.2 or later
(9150) or 7.5 or later (9150/120).
2 Clear parameter RAM. Hold down <Command> <Option> <P>
<R> during startup but before “Welcome to Macintosh”
appears.
3 Replace the logic board with part number 661-0993 and
retain customer’s SIMMs. (Note: This problem occurs only
on the 80 MHz version of the WS 9150 and only during
periods of heavy SCSI Bus activity (for example, when using
backup programs or disk arrays).