As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. EMERGENCY DECLARED. BOS-ORD FLIGHT RETURNED TO BOS ACCOUNT STABILIZER TRIM INOPERATIVE. LANDING UNEVENTFUL. REMOVED AND REPLACED STABILIZER TRIM ACTUATOR PER AMM 27-41-71, MACH TRIM ACTUATOR PER AMM 22-11-24 (AALA20170822006), AND ELEVATOR POSITION SENSOR PER AMM 22-11-30 (AALA201708249017). OPERATIONAL CHECK GOOD.