Precor C960 Service Manual page 35

5. At this point the lift fuse is good, but there is no AC voltage on the lift capacitor when the lift
is actuated. There are three potential causes for this condition. They are lower logic/lift PCA,
ribbon cable or upper PCA. There are no good means of troubleshooting these components
other than substituting known good components. Replace only one component at a time. If
the component that you replaced does not correct the problem, replace the original
component. Try substituting the lower PCA first, the ribbon cable second and the upper PCA
third.
6. If you have performed all of the above procedures and have been unable to correct the
problem, call Precor Customer Support.
7. Using an ohmmeter, measure the resistance across the lift capacitor terminals. The lower
logic/lift PCA resistance should be extremely high (megohms), the capacitor resistance
should be extremely high (megohms) and the lift motor winding should read approximately
34W or 122W. If it measures significantly high or open (•), replace the lift motor.
8. If the resistance measurement in step 6 was approximately 34W (120 VAC units) or 122W
(240 VAC units), replace the lift capacitor. If you have performed all of the above procedures
and have been unable to correct the problem, call Precor Customer Support.
9. Typically, when the lift is able to physically move but causes a lift error, the problem is in the
lift position identification system (lift potentiometer or lift calibration).
10. Measure the voltage between the red wire (term. 1 of J1) and the black wire (term 3 of J1)
on the lower PCA. The voltage should measure approximately 5 Vdc. If the voltage is 0 Vdc
or significantly low, continue with step 11. If the voltage is correct go to step 12.
11. Disconnect the J1 connector from the lower logic/lift PCA. Measure the voltage between
term.1 of J1 and term 3 of J1on the lower PCA. If the voltage is still 0 Vdc or significantly low
replace the lower logic/lift PCA. If the voltage is correct with the J1 connector disconnected,
replace the potentiometer assembly.
12. Disconnect the J1 connector from the lower logic/lift PCA. With an ohmmeter, measure the
resistance between the red wire (term. 1 of J1) and the black wire (term 3 of J1). The
measurement should be approximately 10KW. With an ohmmeter, measure the resistance
between the red wire (term. 1 of J1) and the white wire (term 2 of J1)and measure the
resistance between the white wire (term. 2 of J1) and the black wire (term 3 of J1). The sum
of the last two measurements should total approximately 10 KW.
13. If either of the two 10 KW measurements are open (•) or significantly low or high, replace the
potentiometer assembly.
14. If you have performed all of the above procedures and have been unable to correct the
problem, call Precor Customer Support.
15. If the lift motor operates but creates a lift error (error 40, 41 or 42) go to step 22. If the lift
motor will not move continue with step 2.
C960 Series Commercial Treadmill
Page 35