ALARM 220

Turret Position Sensor Malfunction

Turret encoder (Tamagawa TS1857N16 on QT15N) is failing — the station-1 indicator LED on the encoder lights randomly across other stations instead of only at...

Controls: T-32, T-32B
Machine series: Quick Turn

Causes

Turret encoder (Tamagawa TS1857N16 on QT15N) is failing — the station-1 indicator LED on the encoder lights randomly across other stations instead of only at station 1.
- Zebovskyforum
  Alarm 220: Turret position sensor malfunction. Tools 1–8 index correctly, but the issue occurs with tools 8–16. I understand that the most likely cause is the encoder (in my case, a Tamagawa TS1857N16). I've noticed that…

How to clear it

1
Confirm the encoder LED only lights at station 1. If it lights at other stations, the encoder is bad. There is some radial adjustment range where the LED stays on at station 1 — center the encoder within that range when reinstalling.
- cnctoolcatforum
  The red light on the encoder is supposed to only come on at station 1. So if it is coming on randomly throughout the indexing stations, chances are your encoder is bad. There is some radial adjustment with the encoder mo…
2
When ordering a replacement, match station count: most QT15s shipped as 8 or 12-station; a 16-station replacement encoder is a different part.
- cnctoolcatforum
  Most QT15's were 8 or 12 turret station machines, so be sure if you buy a different encoder it is for 16 stations.

Confidence: medium · Single PM thread but the diagnostic technique (LED-at-station-1 only) and the part number (Tamagawa TS1857N16) are specific and operator-verified.

First sourced: 5/21/2026