As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT ALTERNATOR WAS REPORTED INOPERATIVE. TROUBLESHOT AND FOUND ALTERNATOR GEAR RETAINING NUT HAD UNSCREWED FROM THE ARMATURE SHAFT. DISCOVERED INTERNAL CONDITION OF ARMATURE SHAFT TO BE WORN AT BEARING POINT. ALTERNATOR SHAFT SEIZED AND ROTATION OF THE GEAR SHEARED THE COTTER PIN AND ALLOWED THE RETAINER NUT TO COME OFF. THIS ALTERNATOR HAD APPROXIMATELY 130 HOURS SINCE OVERHAUL.