Precor 9.31 Service Manual page 26

3. Measure the voltage between terminal 1 of J3. (red wire) and terminal 4 of J3 (black wire) on
the lower PCA, see Diagram 5.2. The voltage should read approximately 5 Vdc. 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 J3 connector 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 logic PCA.
4. If at this point the speed sensor output is good, but a speed error occurs, replace the upper
PCA.
5. If you have performed all of the above procedures and have been unable to correct the
problem, call Precor Customer Support.
9.31, 9.33, 9.35 Treadmill
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