A

PSM External Cooling Fin Fan Stop

Fanuc · Series 30i CNC

What does A mean?

This alarm indicates that a cooling fan associated with the external cooling fin of the Power Supply Module (PSM) has stopped. This failure impairs the module's ability to dissipate heat effectively, risking overheating of power components if not resolved promptly. It can also be triggered by internal connection issues.

Common Causes

  • Cooling fan of the external cooling fin is broken or jammed.
  • Poor installation of the control printed-circuit board, causing loose connectors between the control and power printed-circuit boards.

Repair Steps

  1. 1

    Check whether the cooling fan of the external cooling fin rotates normally.

  2. 2

    Replace the cooling fan of the external cooling fin if it is not functioning.

  3. 3

    Ensure the control printed-circuit board is securely installed, verifying all connectors between it and the power printed-circuit board are tight.

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Verified technical data. Last updated: March 2026
Fanuc Error A: PSM External Cooling Fin Fan Stop — Troubleshooting Guide | ErrorLib