As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOUND FACTORY DEFECT WHILE PERFORMING FIRST 500-HOUR INSPECTION MAGNETO WITH TT 477.6 IN ACCORDANCE WITH SERVICE SUPPORT MANUAL X42001. COIL TAB HAD NOT BEEN INSTALLED PARALLEL WITH HOUSING TO COVER MATING SURFACE, AS SPECIFIED IN 6-2.4 5.C. THIS HAD RESULTED IN EXCESSIVE WEAR ON BOTH THE COIL TAB AND THE CARBON BRUSH.