As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE, RIGHT GENERATOR DRIVE LIGHT FLASHING. GENERATOR DRIVE WOULD NOT DISCONNECT. RIGHT GENERATOR CONTROL SWITCH TURNED OFF, APU STARTED. REPLACED IDG, AND GCU. SYSTEM OP CHECKED OK. TESTED UNITS IN SHOP, COULD NOT FIND FAULT. OVERHAULED AS A PRECAUTION AND RETURNED TO STOCK.