As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS RETURNING TO FIELD WITH A TRIM PROBLEM CREW REPORTED ON THE GROUND THAT THE MAIN PITCH TRIM WAS INOP FOLLOWED THE AOM RETURNED TO LAX. REMOVE AND REPLACE HSCU IAW EMB 140 AMM 27-40-01, OPS CHK GOOD. AIRCRAFT RETURN TO SERVICE.