Fanuc alarm 940: PCB INSTALLATION ERROR
system alarm · Fanuc 0i-D
What it means
The combination of printed circuit boards installed in the control does not match the configuration recorded in the system software - typically a board fitted in the wrong slot, an unsupported option board, or a board whose specification code does not agree with the machine's built specification. Detected at power-up before normal operation starts.
Likely causes
- Option board installed in incorrect slot
- Wrong or mismatched PCB specification fitted after service
- Board not fully seated so its ID cannot be read correctly
Triage note: Check the board specification code against the machine tool builder's specification before replacing anything.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
- Request a quote →
Correct option/main PCB per machine specification drawing
backplane · Check if others ruled out
Need the part urgently?
Send us alarm 940 with your machine details — typical RFQ turnaround is 24–48h.