972

NMI Alarm in Other Board

Fanuc · Series 20 CNC

What does 972 mean?

This alarm indicates a Non-Maskable Interrupt (NMI) originating from a board other than the BOC or SLC within the Fanuc Series 20 CNC system. This suggests a critical hardware malfunction on an auxiliary or expansion board, leading to a system halt.

Common Causes

  • Faulty auxiliary board (e.g., graphics board, I/O expansion board) or its associated circuitry.
  • Memory error on the affected 'other' board.
  • Power supply irregularities to the affected board.
  • Loose or improperly seated auxiliary board.
  • Physical damage to the board.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power cycle the CNC system to attempt a reset of all components and clear the NMI.

  2. 2

    Identify any auxiliary or expansion boards installed in the CNC. Inspect them for proper seating and connection.

  3. 3

    Verify stable and clean power supply to all installed boards within the CNC cabinet.

  4. 4

    Inspect all installed boards for any visible damage, such as burn marks or damaged components.

  5. 5

    If possible, remove non-essential auxiliary boards one by one and power cycle to isolate the faulty board.

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Verified technical data. Last updated: March 2026

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