As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER START WITH NR 1 GENERATOR ON APU, SWAPPED GEN TO NR 1 ENGINE AND NR 1 GEN BUSS SOURCE OFF LIGHT CAME ON. ACFT GROUNDED. REMOVED FILTERS FROM REMOVED IDG, NO CONTAMINATION NOTED IAW AMM 24-11-11. REMOVED AND REPLACED THE NR 1 IDG IAW AMM 24-11-11. LEAK CHECKED GOOD, GROUND VERIFICATION SUCCESSFUL.