Originally Posted by
memoryman
From Fanuc maintenace manual:
A watchdog error or RAM parity error occurred in the circuit on an axis control card.
Alarm 920 indicates that either of the above errors occurred in the control circuit for axes 1 to 4. Alarm 921 indicates that either of the above errors
occurred in the control circuit for axes 5 to 8.
The axis control cards, CPU card, or motherboard (main CPU board) may be defective.
You may have to swap/replace any of: the axis control cards, CPU card, or motherboard (main CPU board).