As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
On takeoff at 1000 feet the flight crew experienced rapid yaw movements to both left and right. Required full yoke deflection to maintain control of the aircraft. COM complied with and both yaw damper and rudder servo were turned off. Flight returned to an uneventful landing back at MEM. Maintenance replaced the stablizer augmentation computer and aircraft returned to service.