Applicable Systems
Series 0i
Series 16/18/21
Alpha
Beta
Symptoms
A watchdog timer alarm was detected. Replace the main board.
Possible Causes
- RAM/ROM hardware failure
- CPU malfunction
- Watchdog timer expired
- Power supply or fuse fault
Troubleshooting Steps
- Step 1: Record all alarm information displayed on the CNC screen
Complete alarm information captured - Step 2: Power cycle the CNC system
System restarts; check if alarm clears - Step 3: If alarm persists, check the main board and servo boards for visible damage
No visible damage or burn marks - Step 4: Replace the faulty main board or servo board as indicated by the alarm
New board eliminates the system alarm
How to Reset
To reset system alarm 920: 1) Record all alarm information. 2) Power cycle the CNC. 3) If alarm persists, replace the indicated board (main board, servo board, etc.). 4) Re-load all system parameters and programs. Caution: System alarms indicate serious hardware faults; professional service is recommended.
Frequently Asked Questions
- Q: What does 920 mean on Fanuc FANUC 0/0i/30i Series?
A watchdog timer alarm was detected. Replace the main board.
- Q: How do I fix 920 on Fanuc?
Follow the troubleshooting steps: Record all alarm information displayed on the CNC screen
Source: FANUC CNC System Alarm Manual (doc.eleok.com)
Category: CNC