APM
All alarm codes
ALARM 250

Spindle start misoperation

Spindle rotation command was given while the chuck was not closed (mis-chucking), or the chuck open/close check sensor is mis-adjusted

Controls
T-Plus, T-32, T-32B, Fusion 640T, Matrix, Mazatrol Fusion 640MT Pro
Machine series
Quick Turn, Integrex, Quick Turn Nexus, Mazak Integrex 200-III

Causes

  1. Spindle rotation command was given while the chuck was not closed (mis-chucking), or the chuck open/close check sensor is mis-adjusted

    • HelmanCNC — Mazak Alarm 250industry_blog
      A spindle rotation command can be given even though the chuck is not closed. After closing the chuck using the chuck clamp command, designate the spindle rotation command. ... The chuck open/close check sensor may be imp…

  2. M3/M4/M16/M17/M18/M19 was commanded while in the milling mode (program/mode mismatch)

    • HelmanCNCindustry_blog
      The M3, M4, M16, M17, M18 or M19 command given in the milling mode is a program error that requires correcting the program or switching to the turning mode.

  3. Tailstock quill not fully retracted/extended, or tailstock switch in neutral

    • HelmanCNCindustry_blog
      the tailstock quill must be in the fully retracted or extended position, and the tailstock switch kept at the retract/extend position. Even if it were fully retracted but the switch was in neutral, the spindle would not …

  4. A spindle rotation command was given during mis-chucking, OR the chuck was not closed, OR a rotation command was given together with an orient command, OR rotation was commanded without TOOL EYE at the backward end, OR alarm 297 CHUCK PRESSURE DOWN or 296 TAIL SLEEVE PRESSURE DOWN was active.

  5. Machine setup keyswitch is in the ON position — manual spindle rotation is disabled while in setup mode.

    • clutch73forum
      the problem was that the machine set up switch key has to be in the off position to enable manual spindle rotation. I missed that.

  6. Chuck-clamping direction (OD vs ID) is set wrong — the control thinks the chuck is in an inoperable state for the current part.

    • Casvinforum
      Hit the wrench soft key button and chuck info comes up light should flash for od or id clamping then after you change it push the foot peddle.

  7. Hydraulic chuck cylinder limit switches need adjustment — neither the open nor closed proxy is making.

    • moonraikerforum
      If it's a brand new machine, and assuming that you have a hydraulic chuck, check the operation of the limit switches on the chuck cylinder. One of them may need a slight adjustment.

  8. Spindle Start sequence on Integrex 200-III with 640MT Pro reached a misoperation condition — typically a missing prerequisite signal (door, clamp, gear shift) when the spindle was commanded.

    • Fabian Achavalyoutube
      Mazak Integrex 200III_MAZATROL FUSION 640MT Pro_Alarm 250 Spindle Start Misoperation Part 1

How to clear it

  1. 1

    Close the chuck via the chuck clamp command, then re-issue spindle rotation. If still active, verify chuck open/close sensor adjustment.

    • HelmanCNCindustry_blog
      After closing the chuck using the chuck clamp command, designate the spindle rotation command.
  2. 2

    If the machine has a tailstock, confirm quill is at the full retract or full extend limit AND the tailstock switch is at the corresponding position (not neutral).

  3. 3

    If in milling mode and the M-code is a spindle code (M3/M4/M16-M19), switch to turning mode or correct the program.

  4. 4

    Close the chuck and start operation with the workpiece gripped. If the chuck open/close check sensor is improperly adjusted, check the sensor (PLC X440/X441).

  5. 5

    Retract the TOOL EYE. Check the backward end sensor (PLC X445).

  6. 6

    Close the door and start the spindle rotation (PLC inputs X15, XA).

  7. 7

    Turn the machine setup keyswitch to OFF, then try the spindle start again.

    • clutch73forum
      the machine set up switch key has to be in the off position to enable manual spindle rotation.
  8. 8

    Open the chuck data page (wrench soft key) and verify ID vs OD clamping selection matches the actual workholding. Cycle the foot pedal after changing.

    • Casvinforum
      Hit the wrench soft key button and chuck info comes up light should flash for od or id clamping then after you change it push the foot peddle.
  9. 9

    Two-part troubleshooting series — Part 2 (cQZt22-94UI) continues the diagnostic. Walk through the spindle-start interlock chain in the PLC ladder.

    • Fabian Achavalyoutube
      Mazak Integrex 200III_MAZATROL FUSION 640MT Pro_Alarm 250 Spindle Start Misoperation Part 2

Additional notes

Best-documented PLC alarm in this dataset — multiple cause branches each with explicit remedy.

Confidence: high · Auto-promoted to HIGH — cross-verified across 4 independent research runs (research_alarms_2026-05-21_partners, research_alarms_2026-05-21_official, research_alarms_2026-05-21_forums, research_alarms_2026-05-21_social).

First sourced: 5/21/2026