I have an MDC2250 controller running a rover. During startup after a rough terrain test, I had a short circuit fault. I found that a couple of strands of wire had broken out of a soldered connection and shorted the motor terminal to ground. After repairing, I now have a slight rhythmic ( 5 sec on/5 sec off) buzzing sound while drawing almost 2 amps. The controller eventually gets to an overheat situation.