My Proform pt6.0 incline won't work , how do I fix it?

I have removed the cover to the motors,inspected and cleaned. The boards power up when turned on. With the cover off, I'll press the incline button on the console and I can hear the pulses sent to motor, the motor doesn't respond. I'll keep hold it down till it gets to 10 degrees, then depress the decline. You can here the motor start to respond, then stop,then you get the pulses again. Do you have any suggestion on where to go from here?