Replaced the transistor on the MPU 327 , the diode , the coil , and the sleeve. Powered back up and sling tried to lock up again . Disconnected power before burned up transistor but got better of the board. Now have burned board and right sling that tries to lock up. The board still works just a little toasty. Thought I saw a spark in area under playfield near center drops or ball lock on lower pf. Fearful of trying to turn on . Any help is appreciated. Thanks.