As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, ONE GENERATOR BECAME INOPERATIVE. RETURNED TO FIELD WHEN UNABLE TO START APU. METAL PARTICLES FOUND IN MAG PLUG BOSS. BOSS WAS BROKEN WITH TWO PIECES OF BRASS. ONE WEDGED IN CHECK VALVE OF BOSS. REPLACED CSD, OIL COOLER, AND CHANGED NR 1 GENERATOR. ACCOMPLISHED APU FADEC BITE TEST. FAULT HISTORY SHOWS NO FAULTS FOR PREVIOUS 7 STARTS. STARTED APU SEVERAL TIMES, OPS CHECK NORMAL.