As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOLT ATTACHING ALTERNATOR ADJUSTING BRACKET TO ENGINE FAILED. THIS ALLOWED THE ALTERNATOR TO MOVE UNTIL ELECTRICAL TERMINAL CONTACTED A GROUND CAUSING A DIRECT SHORT. THE BOLT WAS A NON-STANDARD BOLT OF UNKNOWN ORIGIN. UNAPPROVED PART.