As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT TOP OF DESCENT IN VNAV MODE AUTO THROTTLES DISCONNECT UPON REACHING FLIGHT IDLE. THROTTLES DID NOT DISCONNECT IN VERT SPEED DESCENT UPON REACHING FLIGHT IDLE POSITION, ONLY WHEN USED DURING VNAV WOULD THE AUTO THROTTLES DISCONNECT. GROUNDED - YES. REMOVED AND REPLACED #1 CAPTAINS SIDE AUTO THROTTLE SERVO MOTOR REF AMM 22-31-91-020-801,22-31-91-400-801 OPS CHECKS GOOD.