As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AT CRUISE ALTITUDE, NR 1 STARTER/GENERATOR VOLTMETER INDICATED ERRATIC INDICATIONS THEN WENT TO ZERO. GENERATOR SELECTED OFF. ON RETURN LEG, GENERATOR FAILED. COMMUTATOR SEGMENT FOUND BROKEN OFF AND HAD DESTROYED ALL BRUSH ASSEMBLIES.