APM
All alarm codes
ALARM 121

Overtravel (X axis)

Parameters were lost after backup battery died — the X-axis offset reads as '****.****' which the control treats as outside the soft-limit envelope.

Controls
T-32, Fusion 640T
Machine series
Slant Turn, Quick Turn

Causes

  1. Parameters were lost after backup battery died — the X-axis offset reads as '****.****' which the control treats as outside the soft-limit envelope.

    • jdecuirmforum
      The battery died (Silver and black one behind the panel) and Some parameters was lost. I recovered using the Maintenance tool inside the Mainte Folder, recovering the backup and flashing the SRAM, but the problem is at t…

  2. A proximity sensor that the slide passes over has gone bad. Swap the X and Z proxy connections — if the alarm follows the sensor to Z, the original X proxy is the culprit.

    • cameramanforum
      check out the proxy the slide runs across. It could have gone bad. I like to switch z and x around, if the alarm is then in Z, then its the proxy.

How to clear it

  1. 1

    After making a parameter change, fully power-cycle the machine: main switch OFF 5 sec, ON 5 sec, OFF 5 sec, ON 5 sec, OFF 5 sec, then power back up. A single power cycle is not always enough on the 640T.

    • cameramanforum
      After making a parameter change like this, did you kill the main power to the machine twice? I was told by Mazak when we make these changes, main switch off for 5 seconds, on for 5, off for 5, on for 5, off for 5 then po…

Confidence: high · Two PM threads from the same machine family (Slant Turn 50N with 640T) describe identical battery-loss origin and the multi-cycle power-down recovery. Sensor-swap diagnostic is operator-tested.

First sourced: 5/21/2026