As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAGNETO INOPERATIVE BELOW 1,000 RPMS. OK AT 1,700 RPMS PER THE P.O.M. PILOTS HAD DONE A MAG CHECK AT IDLE WHICH LEAD TO THE DISCOVERY. OPENED MAGNETO FOR INSPECTION. TESTED COIL AND FOUND SECONDARY WINDING. RESISTANCE TOO HIGH BY FACTOR OF 10.