Precor C842 Service Manual page 32

5. If either ohmmeter readings is incorrect, perform the same ohmmeter readings using a
strong external magnet instead of the magnet on the secondary pulley. If the ohmmeter
readings are still incorrect, replace the speed sensor. If the ohmmeter readings are correct
using an external magnet, adjust the gap between the magnet, mounted on the secondary
pulley, and the speed sensor to approximately 1/8 inch. Repeat the ohmmeter
measurements in step 3. If either ohmmeter reading is incorrect, replace the secondary
pulley (with magnet). Skip to step 6.
6. Replace the lower PCA. Check the lower PCA as in step 1.
7. If you have performed all of the previous tests and have not been able to locate the trouble,
call Precor customer support.
8. The C842 and C846 version 2 do not use a speed sensor like the C846 version 1 units.
Instead the system monitors one of the three phase generator windings. The system
monitors AC zero cross. The monitoring system notes every time the generator AC voltage
passes through zero volts. By counting the zero cross rate, the system knows how fast the
generator is turning. The system calculates the user RPM from the generator speed. If
9. It is highly unlikely that the RPM reading could be present but incorrect. If this condition
should occur, replace the lower PCA.
C842, C842i, C846, C846i Upright and Recumbent Cycle
Page 32