What was found
(CAN) ON CLIMBOUT, ELEC TRIM WAS OPERATED, IT WOULD ONLY MOVE 1.5 DEG FROM FULL NOSE UP, COULD NOT BE MOVED MANUALLY. AC RETURNED TO DEPARTURE AIRPORT. ELEV TRIM WAS STILL JAMMED ON GROUND ELECTRICALLY AND MANUALLY. INSP OF ACTUATOR MOTOR, IN TAIL SECTION, REVEALED THAT DRIVE HAD SHEARED AT END OF ACTUATOR. ACTUATOR IS CONNECTED TO ANOTHER CABLE DRUM UNIT WITH UNIVERSAL JOINT. ACTUATOR ASSY IS CONNECTED TO 1 ELEV TRIM CABLE WITH BRIDAL CABLE, DRUM UNIT IS CONNECTED TO OTHER ELEV TRIM CABLE WITH A BRIDAL CABLE. WHEN ACTUATOR DRIVE SHEARED, BRIDAL CABLE OF DRUM UNIT AND UNIVERSAL JOINT JAMMED ELEVATOR TRIM CABLE, SO THERE WAS VERY LITTLE MOVEMENT OF TRIM SYS. REASON FOR ACTUATOR DRV BREAKING IS UNKNOWN.