Fanuc alarm 951: PMC WATCH DOG ALARM (NC)
system alarm · Fanuc 0i-D
What it means
Watchdog timeout of the PMC processor - ladder CPU stopped running
Likely causes
- PMC module hardware failure
- main board fault
- +5V rail instability
Triage note: Verify cabinet +5V and reseat boards before ordering; persistent 951 = main board exchange (PMC is not field-repairable on 0i-D)
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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A20B-8200-0740
Main CPU Board (0i-D) · Primary suspect
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A16B-1212-0100
Power Check Board / +5V monitor (legacy cabinets) · Check if others ruled out
Need the part urgently?
Send us alarm 951 with your machine details — typical RFQ turnaround is 24–48h.