Precor C954i Service Manual download pdf (Page 23)

C954, C956 Treadmill

Page 23

Procedure 5.3 - Troubleshooting the Speed Sensor

Note:

The speed sensor is a hall effect sensor that emits a pulse when a flywheel lobe passes between

its transmitter and receiver. The speed control circuit processes the pulse train emitted by the

speed sensor. The speed sensor signal is a real time representation of the operating speed of

the treadmill. The speed control circuit compares the real time speed (speed sensor output) with

the speed that it expects the treadmill to be operating at and acts accordingly to control treadmill

speed or initiate an error code sequence, if necessary. Typically, if a problem exists with the

speed sensor the drive motor will operate (perhaps only briefly) before a speed related error

occurs (errors 20-26).

1. Set the treadmill circuit breaker in the “on” position. Using a DC voltmeter, measure

the voltage between terminal 3 of J2 (green wire) and terminal 4 of J2 (black wire) on

the lower PCA. Slowly, rotate the drive motor flywheel. The voltage should read

approximately 5 Vdc when a flywheel lobe is between the speed sensor “legs” and

approximately 0.25 Vdc when a flywheel lobe is not between the speed sensor “legs”.

Diagram 5.3 - Speed Sensor Mounting

2. If the voltages in step 1 are correct, go to step 5. If the voltage in step 1 is 0 Vdc or

significantly low when a flywheel lobe is between the speed sensor “legs, continue with step

3. Measure the voltage between terminal 1 of J2 (red wire) and terminal 4 of J2 (black wire) on

the lower PCA. The voltage should read approximately 5 Vdc.

Flywheel

Speed

Sensor

1 2 ... 18 19 20 21 22 23 24 25 26 27 28 ... 72 73

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Precor C954i Service Manual Page 23