Procedure 5.2 - Troubleshooting The Lift System - Precor 9.31 Service Manual

Procedure 5.2 - Troubleshooting the Lift System

Lift System Description:
The lift system on these units consists of an AC line voltage driven lift motor (120 Vac), and an
internal 1 KΩ potentiometer for lift position identification. The lift motor contains two motor
windings, one to operate the motor in an "upward" direction and the other to operate the motor in
a "downward" direction. As the lift motor is operated, the motor also rotates the potentiometer via
an internal gear system. Therefore, the position of the lift system can be determined by
monitoring the value of the internal potentiometer. The lift motor is initially set at a known starting
position (calibration, See Procedure 4.1), subsequent motor movement is tracked via the
potentiometer resistance reading.
Note:
All resistance measurements must be performed with power removed from the treadmill.
Performing resistance measurements with voltage applied may damage your ohmmeter.
Procedure
1. If the lift motor operates but creates a lift error (error 40 or 42) go to step 16. If the lift motor
will not move continue with step 2.
2. Set the treadmill's circuit breaker in the "off" position and remove the AC line cord from the
AC outlet.
3. Remove the F2 (Lift AC) fuse from the lower PCA. Using an ohmmeter, check the resistance
of the F2 fuse. See Diagram 5.2. The fuse should measure approximately 0.1 Ω or less. If
the fuse is open or high resistance, replace the fuse.
Diagram 5.2 - Lower PCA
J1 Connector
9.31, 9.33, 9.35 Treadmill
Fuse F2
J3 Connector
J7 Connector
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