As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APPROX 15 MINS AFTER TAKEOFF, AC LOST NR 2 ELECTRICAL GENERATOR. APU WAS INEFFECTIVE IN POWERING ESSENTIAL SYSTEMS ON THE PLANE, SO CAPT ELECTED TO RETURN TO DEN FOR REPAIRS. *S/D* REPLACED GENERATOR LINE CONTACTOR NR 2 (GLC2) AND NR 2 GENERATOR CONTROL UNIT (GCU).