Procedure 5.3 - Troubleshooting The Speed Sensor - Precor 9.23 Service Manual

Procedure 5.3 - Troubleshooting the Speed Sensor

Note: The speed sensor is a reed switch mounted beside the drive roller pulley. There are two
magnets in the drive roller pulley that activates the reed switch (speed sensor) once each
revolution. The speed sensor's signal is sent to the speed controller circuit via the lower PCA and
is used to determine the treadmill's actual running speed.
Typically, when the speed sensor is not functioning, the drive motor will operate briefly when
started and then shutdown and display a error. 26
1. Set the on/off switch in the "off" position and remove the AC power cord from the AC outlet.
Diagram 5.4 - Speed Sensor
Speed
Sensor
2. Remove the treadmill's hood.
3. Remove the JK2 connector from the lower PCA. Refer to Diagram 5.2.
4. With an ohmmeter measure between the two pins on the JK2 connector and slowly push the
running belt to rotate the drive roller. When the magnet is not opposite the speed sensor the
meter reading will be open (∞). When the magnet in the drive roller is opposite the speed
sensor, the meter reading should be approximately 0Ω.
5. If the measurements in step 4 are not correct, repeat those measurements using a strong
hand held magnet to operate the speed sensor.
6. If the measurements in step 5 are now correct, replace the drive roller. If the measurements
are still incorrect, replace the speed sensor per Procedure 6.4.
7. If you have performed all of the procedures above and have been unable to correct the
problem, call Precor customer support.
20081-118
9.23, 9.27 Treadmill
Magnet
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