Apple Performa 6400/180 - Manual (Page 76)

Troubleshooting Symptom Charts/System - 2
Symptom Charts
System
System
intermittently
crashes or hangs
1 Verify that system software is version 7.5.3 or later.
2 Verify that software is known-good.
3 Verify that software is PowerPC-compatible (contact
developer).
4 Clear parameter RAM. Hold down Command-Option-P-R
during startup, but before “Welcome to Macintosh” appears.
5 Disconnect all external devices attached (except monitor) and
restart.
6 Replace DIMMs.
7 Replace logic board. Retain customer’s DIMMs.
8 Replace power supply.