Tormach ATC Operator's Manual page 30

Sensor is Defective
Any magnet can be used to verify whether or not the
sensor is working. If you bring a strong magnet near the
TRAY IN or TRAY OUT sensors they should return TRUE. If
the sensor is working, you can skip to the "Sensor is out of
adjustment" section.
If the sensor is not working, you will need to determine
whether the sensor itself is defective or if there is a short
in the wiring.
NOTE: The TRAY OUT sensor is held in place by
a band clamp – if this clamp is over tightened it
will prevent the sensor from working. You might
try loosening the band clamp as a first step in
diagnosing a bad TRAY OUT sensor.
To distinguish between a wiring problem and a sensor
problem, you will need to Ohm out the sensor with a
multimeter:
1.
Remove the motor cover, then remove the top of the
stepper motor's electrical junction box:
UM10081_TTS_ATC_PCNC1100_1013A
2.
Disconnect the 20 pin Molex connector. The female
side goes to the motor and sensors:
3.
Touch your probe leads to the pins corresponding to
the sensor of interest:
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