As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW RETURNED THE AIRCRAFT TO LAX FOLLOWING THE NR 1 GENERATOR DROPPING OFFLINE AT TOP OF CLIMB. UNABLE TO CONTINUE ETOPS. CORRECTIVE ACTION: MAINTENANCE REPLACED THE NR 1 ENGINE IDG, PER B757 AMM 24-11-01. THE GENERATOR FEEDER CABLES ALL CHECKED SATISFACTORY. OPERATIONAL CHECK WAS NORMAL. THE AIRCRAFT HAS RETURNED TO SERVICE.