As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INFLIGHT, CREW NOTICED NOISE IN LT ENGINE, FOLLOWED BY NR 1 GENERATOR FAILURE. INSPECTORS FOUND AFT BEARING ON LT STARTER GENERATOR HAD COMPLETELY FAILED ALLOWING ARMATURE TO HIT FIELD POLES. S/G HAD APPROXIMATELY 500 HOURS SINCE LAST OVERHAUL. EXCHANGE STARTER-GENERATOR AND GENERATOR CONTROL UNIT INSTALLED SYSTEM CHECKED, OK. CAUSE OF BEARING FAILURE UNKNOWN. SENT FOR CORE EVALUATION. SUSPECTED CAUSE OF FAILURE, MANUFACTURING DEFECT IN BEARING.