As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER T/O ON FLIGHT 2904 MAIN PITCH TRIM FOUND TO BE INOP. MAIN PITCH TRIM FAILED ON CLIMBOUT, INOP FROM BOTH CAPTS AND F/O'S SIDE. STANDBY TRIM OPERATES NORMALLY AFTER ABOUT 10 MINUTES MAN TRIM STARTED WORKING MOMENTARILY. AIR TURNBACK TO DTW. MAINTENANCE CLEANED CANNON PLUG A MAIN PITCH TRIM ACTUATOR.