As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APU MAINTENANCE, THE AC GENERATOR WAS REMOVED. THE INPUT DRIVESHAFT WAS FOUND DECOUPLED FROM AC GENERATOR. THIS SHAFT IS HELD IN PLACE BY A SINGLE SCREW. IF THE SCREW SHEARS OFF OR BACKS OUT, IT CAN CAUSE INTERNAL DAMAGE OR FAILURE TO THE AC GENERATOR.