What was found
(CAN) FLIGHT CREW HAD A AUTOPILOT DISCONNECT IN CRUISE FLIGHT THEY SHUT DOWN AUTOPILOT SYSTEM AND CONTINUED FLIGHT HOME. MAINTENANCE TESTED AUTOPILOT SYSTEM AFTER RESETTING C/B AND SYSTEM WORKED AS PER M/M.THEY THEN CARRIED OUT THE TEST ON THE HORIZONTAL STAB TRIM, WHEN THEY GOT TO THE PROCEDURE TO TESTTHE ALTERNATE TRIM THEY FOUND IT TO BE U/S. FURTHER INSPECTION REVEALED THAT THE SECONDARY MOTOR WAS SEIZED. A REPLACEMENT UNIT WAS INSTALLED AND TESTED SERVICEABLE.PITCH TRIMACTUATOR HAD 808.7 HR S AND 890 CYCLES. THIS IS THE SECOND FAILURE WE HAVE HAD ON THESE UNITS WITH LESS THAN 1000 HRS.