NMI Alarm by Unknown Cause

What does 973 mean?

This alarm indicates a Non-Maskable Interrupt (NMI) has occurred within the Fanuc Series 20 CNC, but the system could not specifically identify the source or cause of the NMI. This signifies a severe, unidentifiable hardware or fundamental software issue, leading to a system halt.

• Transient or intermittent hardware fault not captured by specific NMI handlers.
• Severe power supply instability or noise affecting multiple components.
• Corruption of critical system firmware or BIOS.
• Motherboard or backplane malfunction affecting bus communication.
• Unforeseen hardware interaction or component failure.

Click steps to track your progress.

1. 1

   Perform a complete power cycle of the CNC system, including removing main power, to ensure a full reset.

2. 2

   Verify all power supply units and their output voltages for stability and correct levels. Inspect for ripple.

3. 3

   Inspect the entire CNC main board, backplane, and all installed modules for any visible damage, loose connections, or signs of overheating.

4. 4

   Check for any strong sources of electromagnetic interference (EMI) around the CNC cabinet.

5. 5

   If the alarm persists and no specific cause can be identified, consider a systematic replacement of the main CNC board as it points to a deep-seated hardware fault.