Troubleshooting The Speed Sensor - Precor Energy Series Service Manual

Troubleshooting the Speed Sensor

1. Disconnect the speed sensor connector from the LPCA JK2 connector.
2. Use a DVM to measure the resistance between two connector pins. Be careful to not damage
the connector pins with the DVM probes.
3. The speed sensor is a normally open switch (open circuit), when the speed sensor magnetic
passes by the speed sensor the switch closes (short circuit. Rotating the take-up roller past the
sensor.
4. Measure the voltage between terminal 1 of JK2 (red wire) and terminal 4 of JK2 (black wire) on
the Lower PCA, see Diagram 5.2. The voltage should read approximately 5 Vdc. If the voltage
is missing or significantly low, disconnect the speed sensor plug from the Lower PCA. Measure
the voltage between pins 1 & 4 of the JK2 connector on the Lower PCA. If the voltage is
approximately 5 Vdc, replace the speed sensor. If the voltage is missing or significantly low,
replace the lower logic PCA.
5. If you have performed all of the above procedures and have been unable to correct the
problem, call Precor Customer Support
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