A failure in the lower PCA overloads the low voltage power supply and causes it to drop below the preset level.
A fault in the interconnect cable (upper PCA to lower PCA) causing the low voltage power supply of the lower PCA to be too low.
A failure in the upper PCA overloads the lower PCA low voltage power supply causing it to be too low.
If the error message is continually displayed when the unit is powered up, the upper PCA needs to be replaced. External causes may make the error appear intermittently.
If the AC input of the unit dips significantly during power-up test sequences, the test could fail and cause the error to appear.
A treadmill connected to a non-dedicated AC circuit can experience this error intermittently.
Determine if the interconnect cable is the cause by substituting a know good cable in place of the current cable. For test purposes, the substitute cable needs to be connected directly between the upper and lower PCA's, without routing the cable internally.
Determine if the upper PCA is the cause by substituting a know good upper PCA for the existing upper PCA.