As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INVESTIGATIONOF REPORTED MAGNETO FAIL, REMOVED LT & RT MAGS AND FOUND LT MAGNETO IMPULSE COUPLING DRIVE PADS AND CAGE WERE BROKEN. DISASSEMBLED LT MAG AND FOUND ROTOR GEAR STRIPPED AND THE BREAKER END ROLLER BEARING HAD FAILED AND COME APART AND JAMED THE MAGNET AND STOPPED THE MAG 300 HRS AFTER 500 HR INSP.