APM
All alarm codes
ALARM 33

SERVO MALFUNCTION 2 (&0000004D, &0004, &0021)

Loose contact inside the control board at the Z-axis encoder connection — random vibration triggered the alarm intermittently.

Controls
SmoothG
Machine series
unspecified Mazak with MDS-E/MDS-EH drives

Causes

  1. Loose contact inside the control board at the Z-axis encoder connection — random vibration triggered the alarm intermittently.

    • Fabian Achavalyoutube
      The root cause on this case was lose contact inside the control board where the Z axis encoder is connected. Random vibrations triggered the alarm.

How to clear it

  1. 1

    Replace the affected servo drive with a known-good unit. Original drive can be sent out for refurbishment.

    • Fabian Achavalyoutube
      The drive was replaced with a brand new one. Original drive is going to be refurbished.

Additional notes

Channel author notes 'There's room for improvement on the assembly design' — implying this is a known weak connection point on the drive.

Confidence: medium · 1 detailed YouTube case study from a Mazak service tech; root cause identified and fix verified, but only a single source.

First sourced: 5/21/2026