As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ELEC GEN SYSTEM L IDG HAS DISCONNECTED OR A PROTECTIVE TRIP OF THE GENERATOR CONTROL BREAKER HAS OCCURRED OR A PROTECTIVE TRIP OF THE BTB HAS OCCURRED. AFTER EXTENSIVE TROUBLESHOOTING FOUND IDG TO BE FAULTY. SUSPECT FAULTY BEARING. REPLACED LEFT IDG PER AMM24-11-01. GROUND RUN CHECKED NORMAL. AC OK FOR SERVICE.