We have a misbehaving turntable. Our child overloaded the microwave glass plate with several pounds of chicken. Far too much. From then on the turntable misbehaves. When you start up the oven it sort of turns and makes a crackle, almost like popcorn. Then after a bit it settles down and starts turning in the other direction (the correct one) and works properly. Strange. Thus it would not seem to be the motor, and probably not the board (though I'm not sure). I'm wondering if the weight of the load it was given compacted or bent the metal in some way that is putting pressure on the turntable mechanism.