What was found
(CAN) AUTO PILOT AND AUTO THROTTLE DISENGAGES C/B C-18 POP OUT. THE DFGS AND AILERON SERVO WERE REPLACED AND FUNCTIONAL CHECK WERE CARRIED OUT, AIRCRAFT RETURN TO SERVICE. ON THE SECOND FLIGHT AUTO PILOT NR 1 TRIP ALONG WITH THE AUTO THROTTLE AND C/B C18 POP OUT. AIRCRAFT STARTED TO OSCILLATED IN FLIGHT. QR A COMPLETED YAW DAMPER OFF RUDDER HYD LEVER - MAN. OSCILLATION STOP.WIRE 2C610Y20RD FOUND SHAFING ATUPPER SECTION OF VERTICAL FIN (28 VAC FEED FOR RT ELEVATOR POSITION SENSOR). WIRE ISOLATED AND AREPAIRED. SYSTEM CHECK SERVICEABLE IAW MM 22-00-00 P202.