Yes, you should try to change the transistors, however they are supposed to be protected from voltage spikes like that generated by plugging/unplugging cables by diodes (next to transistors)... Is anything on the board too hot? (careful, you may burn your fingertips!)
How about cable?
Quote:
Originally Posted by guodong
Thanks, bojan
It's a stepper motor. The motor coils looks ok. The way I burnt was: I turn on the power to controller before plugging in the cable to motor. Do you have any suggestion? Probably have to change the transistors. Still trying to solve it today 
Cheers
Gordon |