As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER TAKEOFF, RECEIVED A PTRIM MAIN INOP WARNING. DECLARED AN EMERGENCY AND RETURNED TO DEPARTURE. BACKUP TRIM WAS STILL OPERATIONAL. ACFT REMOVED FROM SERVICE. R & R THE HORIZONTAL STABILIZER CONTROL UNIT. OPS CHECKED GOOD IAW AMM 27-40-01 AND IAW AMM 27-40-00-700-802-A. ACFT RETURNED TO SERVICE.