Quoted from schudel5:
It might not be the motor board but Q36 on the power driver board that's locked on. Test that transistor first. But yep that's the motor EMI board.
I had this same problem with my dirty harry and i replaced Q36 and everything started to work fine again.
Talking to person who makes the emi motor board, they said that there should never be a problem on that board since there is so little going to it.