5

Low-voltage of Control Power Supply (ECM)

Fanuc · A20B-2101-0390 αi series AC Servo Motor and Spindle

What does 5 mean?

The 24V control power supply voltage to the ECM has dropped below the acceptable threshold. This can lead to improper operation or shutdown of the ECM.

Repair Steps

  1. 1

    Measure the 24V control power supply voltage at the input terminals to the ECM.

  2. 2

    Check the external 24V power supply unit for proper operation and load capacity.

  3. 3

    Inspect the wiring from the 24V power supply to the ECM for voltage drops or loose connections.

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Verified technical data. Last updated: March 2026
Source: Fanuc A20B-2101-0390 αi series AC Servo Motor and Spindle