As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STAB TRIM LWR THAN 0 DEG LEVEL OFF AT 230. TRIM WOULD NOT GO LWR THAN 0 DEG AND THEN IT WOULD GO NOSE UP ON ITS OWN. COMPLIED WITH RED TABS FOR JAM STAB. *S/D* REMOVED AND REPLACED AUTO PILOT STAB TRIM ACTUATOR AND JACKSCREW ACT ASSY PER MM 27-40-31 AND 22-11-21.