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ErrorLib — Industrial Fault Code Library

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970

NMI Alarm in BOC (Base Board Controller)

Fanuc · Series 20 CNC

What does 970 mean?

This alarm indicates a Non-Maskable Interrupt (NMI) originating from the Base Board Controller (BOC) within the Fanuc Series 20 CNC. An NMI is a critical, high-priority interrupt that usually signals a serious hardware malfunction that the CPU cannot ignore, often leading to a system halt.

Common Causes

  • Faulty BOC hardware or associated circuitry on the CNC main board.
  • Memory error on the BOC or related components.
  • Power supply irregularities affecting the BOC.
  • Overheating of the BOC or surrounding components.
  • ESD damage to the BOC.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

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

  2. 2

    Verify stable and clean power supply to the CNC main board, checking for voltage drops or spikes.

  3. 3

    Inspect the CNC main board for any visible damage, such as burn marks or damaged components in the BOC area.

  4. 4

    Ensure adequate cooling inside the CNC cabinet and check for proper fan operation and clear airflow.

  5. 5

    If the alarm persists, it indicates a hardware fault on the CNC main board related to the BOC, requiring replacement of the main board.

Browse all codes in this manual (43)
Verified technical data. Last updated: April 2026

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Source: Fanuc Series 20 CNC
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