APM
All alarm codes
ALARM 394

ATC Malfunction

Backup battery in the ATC servo drive is dead. The alarm appears even though the ATC positions show normal in the maintenance menu and the program will still...

Controls
Fusion 640T
Machine series
Integrex

Causes

  1. Backup battery in the ATC servo drive is dead. The alarm appears even though the ATC positions show normal in the maintenance menu and the program will still run.

    • Joe788forum
      I think you have a dead battery in the drive for the ATC servo.

How to clear it

  1. 1

    Replace the backup battery inside the ATC servo drive (not the main control battery). Re-home after replacement.

    • Joe788forum
      I think you have a dead battery in the drive for the ATC servo.

Confidence: medium · Single source, but Joe788 is a frequent contributor to Mazak threads and the OP's symptom (alarm 394 with normal ATC menu values and program still running) is textbook backup-battery behavior.

First sourced: 5/21/2026