What was found
AIRCRAFT WAS GROUNDED: SHORTLY AFTER TAKEOFF, VERY LOUD HUM FROM COCKPIT FLOOR AREA AND ELECTRICAL SMELL, FOLLOWED BY HUM STOPPING WITH ECAM VENT BLOWER FAULT. MAINTENANCE REPLACED BLOWER FAN (20HQ) PER AMM 21-26-51-000-001-A AND AMM 21-51-400-001-A. MAINTENANCE ALSO PERFORMED SATISFACTORY OPERATIONAL CHECK, NO ELECTRICAL SMELL NOTED.