Procedure 5.2 - Troubleshooting The Lift System - Precor 9.23 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 10 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 briefly and creates a lift error (error 40) go to step 13. If the lift motor
will not move continue with step 2.
2. Set the treadmill's on/off switch in the "off" position and remove the AC power cord from the
AC outlet.
3. Remove the hood from the treadmill.
Diagram 5.2 - Lower PCA
PWM
JK2
POWER
LIMIT
SHUTDOWN
T4 (M-)
T3 (M+)
JK1
JK3
UP
9.23, 9.27 Treadmill
DOWN
JK4
T2 (AC2)
T1 (AC1)
Fuse
MOT DRV
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