I've got an older powerdrive that gave up the ghost a while back. Steers fine but when you apply power to the motor, all you hear is a slight click from the control board. Pretty common with these old motor I think. I wonder if anybody has tried to run one with a rheostat to control the power? I know the control board is supposed to maximize the efficiency of the battery power, thru it's electronics, but could you run it off a rheostat?