As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENG/TRANSMISSION COUPLING, LOWER BEARING OF ACTUATOR WHICH IS CONNECTED TO LOWER SHAFT AND BEARING ASSEMBLY WORE OUT. THIS CAUSED THE ACTUATOR ASSEMBLY TO VIBRATE AND, THEREFORE, ONE BELT TENSION SWITCH TO BREAK. BEARING TOO WEAK TO HOLD UP TO THE PRESSURE AND VIBRATIONS.