As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER T/O AFTER GEAR UP, FELT A/COLL TO THE LEFT, GOT CONTROL OF A/C THAN IT HAPPENED AGAIN. FLIGHT CONTROL SHOWING UPPER RUDDER MOVING TO THE LEFT, THEN SLOWLY GOING BACK TO CENTER. DECLARED EMERGENCY & SHUTOFF UPPER YAW DAMPER COMPUTER, PROBLEM SEEMED TO GO AWAY. REPLACED UPPER YAW DAMPER COMPUTER, ALL OPERATIONS NORMAL.