What was found
DURING INITIAL TAXI OUT FROM GATE, FLIGHT CREW NOTED THAT NR 2 AND NR 3 GENERATORS WOULD NOT PARALLEL. FLIGHT CREW ELECTED TO RETURN TO GATE. AIRCRAFT RETURNED WITHOUT INCIDENT. MAINTENANCE PERSONNEL FOUND NR 3 GENERATOR CONTROL UNIT INOPERATIVE. REPLACED NR 3 GENERATOR CONTROL UNIT GROUND RAN BOTH ENGINES AND PARALELLED GENERATORS. AIRCRAFT RETURNED TO SERVICE. PART MFG BY WESTINGHOUSE. (X)