As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING SCHEDULED 500-HR INTERNAL MAGNETO INSPECTION IT WAS DISCOVERED THAT THE ROTOR DISTRIBUTOR PLATE HAD OVERHEATED AND BECOME LOOSE. THE PLASTIC ROTOR BODY WAS MELTED IN THE VICINITY OF THE PLATE DUE TO ARCING CAUSED BY THE LOOSE PLATE. THERE WAS NO OPERATIONAL INDICATION, THE ENGINE RAN NORMALLY WITH NORMAL MAG DROPS.