As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON A ROUTINE ENGINE OVERSPEED SYS CHECK, WANTED TO INCREASE THE ENGINE RPM SLIGHTLY WITH THE TRIM SWITCH. FOUND UNABLE TO GET THE SWITCH TO DO ANYTHING. ON INSPECTION, MECHANIC FOUND THAT THE LINEAR ACTUATOR WAS INOPERATIVE AND SUBSEQUENTLY REPLACED THAT PART WHICH RESTORED SYS TO WORKING ORDER.