As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THRU FL190 A/P CRUSE TRIM WOULD NOT WORK IN EITHER DIRECTION, NOR WOULD THE MAIN ELC TRIM WORK IN THE NOSE DOWN DIRECTION. RECYCLED THE CUTOUT SWITCHES, BUT STILL DIDN'T WORK. NO STAB TRIM C/B'S WERE POPPED ON THE DESCENT THE TRIM STARTED TO WORK NORMALLY. REMOVED AND REPLACED AUTO PILOT STAB TRIM SERVO IAW MM 22-11-021-2 AND REMOVED AND REPLACED MAIN ELECTRIC STABILIZER TRIM ACTUATOR PER MM 27040-031-2.