As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER STARTING LT ENGINE-GENERATOR WOULD NOT COME ON LINE -NEGATIVE FREQUENCY AND VOLTS. ACFT GROUNDED. AFTER ENG RUN FOUND NO SOURCE VOLTS, FREQUENCY WITH GCU FAULT 1 IDG. R & R 1 ENGINE IDG REF MM 24-11-11-000-801 AND 24-11-00-700-802.