Precor C954 Serivce Manual page 26

4. 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 J2 plug 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 PCA.
5. At this point the speed sensor output is good, but a speed error occurs. There are two
potential causes for this condition. They are upper PCA or lower 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 then the upper PCA, if necessary.
6. 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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C954, C956 Treadmill
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