Turned on my thread mill on one of the programs and the incline ran up to full incline to the end of its stroke and jammed itself to the extent of the gear drive then motor started humming. I took it apart, manually turned the gear drive down and once energized it did the same thing. Seems like a sensor or circuit board problem, no matter what I try the incline goes to max & stalls motor. It doesn't matter if i'm on a program or manual control. Any help is really appreciated.