As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DOWNWIND FOR APPROACH, MASTER CAUTION ELEC NOTICED SOURCE OFF LIGHT ILLUMINATED. RAN SOURCE OFF LIGHT CHECKLIST. GENERATOR SHOWED NO VOLTS OR FREQUENCIES AVAILABLE ON BUSS. ACFT GROUNDED. TROUBLESHOT IAW FIM 24-21 / 801, NR 1 GCU BITE PROCEDURE. FOUND RED IDG FAULT LIGHT ILLUMINATED ON GCU FRONT PANEL. PREVIOUS HISTORY, SAME PROBLEM. SUSPECT A BAD NR 1 IDG. REMOVED AND REPLACED THE NR 1 IDG IAW AMM 24-11-11, OPS AND LEAK CHECKED GOOD.