As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STAB TRIM AND MACH TRIM CAUTION MESSAGE, DISENGAED AFTER TAKEOFF RESELECTED STAB TRIM & MACH TRIM BUT DISCONNECTED AGAIN. AUTO PILOT WAS NOT ABLE TO LEVEL THE AIRCRAFT AT 10'000 FT AND VIOLENTLEY DISENGAGED. RAN QRH FOR STAB & MACH TRIM. WERE ABLE TO RE-ENGAGE BOTH STAB & MACH AND AUTOPIOLT TO RETURN TO DEPARTURE. HAD AP TRIM IS ND & AP PITCH TRIM CAUTION. REMOVED AND REPLACED HSTCU IAW AMM 27-41-01. OPS CHECKED GOOD