I have a Horizon Quantum II treadmill which has a motor control board problem. The motor tested ok and the elevation motor is working. With the motor disconnected I am getting around 20v at the terminals, which I presume should be much higher. I have replaced the Power Diode and the SCR. The FET seems to be testing ok and the schoktty diodes are also testing ok. Can anybody help?

 

First off get a camera..
snap some nice pics and show your work and problem

 

I found a 100k resistor which was reading about 180k. I replaced it but still not working. I then re-soldered the pins on the small IC U2. After I did this and turned on the machine, it worked and is still working. I presume there was a dry-joint at on of the pins of U2. Thanks to everyone for trying to help me. Hope this info helps somebody too.