What was found
WHILE PERFORMING FLIGHT CONTROL TEST ON TAXI CHECK, THE ELEVATOR CONTROL SEEMED TO SNAG OR CATCH ON SOMETHING MIDWAY OF TRAVEL. RETURNED TO GATE. REMOVED AND REPLACED ELEVATOR AUTO PILOT SERVO IAW MM 27-00-03. OPS CHECKS GOOD. P/N ON: 622-5734-002, S/N ON: 5371, S/N OFF: 3893.