As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING GROUND RUN IT WAS NOTICED THAT THE RIGHT MAGNETO WAS INOPERATIVE. UPON TROUBLESHOOTING THE TECHNICIAN REMOVED AND VISUALLY INSPECTED THE RIGHT MAGNETO. DISCOVERED THE ROTOR SHAFT TO BE BROKEN AT THE CAM ATTACH POINT. REMOVED MAGNETO FROM SERVICE AND SENT OUT FOR REPAIR.