What was found
AIRCRAFT WAS NOT GROUNDED: 1 HOUR 40 MINUTES INTO FLIGHT TO CANCUN FLIGHT, AT FL 370, WE STARTED GETTING A CONSTANT NOISE WITH FLOOR VIBRATION. THIS FLOOR VIBRATION COULD BE FELT IN COCKPIT AND ESPECIALLY IN FORWARD GALLEY RIGHT SIDE. IT WAS NOT THE FORWARD LAVATORY FLUSH MOTOR, NOR THE OVENS. THE #1 FA TURNED OFF THE GALLEY AND OVEN POWER. BOTH PILOTS THOUGHT WE SMELLED A MORE ELECTRICAL ODOR. WE WERE WITHIN 200 MILES OF CUN, SO WE DESCENDED TO FL250 AND SLOWED TO 250 KNOTS. THE NOISE AND VIBRATION REMAINED CONSTANT, BUT THE SMELL SUBSIDED. MAINTENANCE DETERMINED THE AVIONICS EXTRACT FAN TO BE THE SOURCE OF TRANSITORY VIBRATION AND SMELL. MAINTENANCE REPLACED THE AVIONICS EXTRACT FAN AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK WITH NO ODORS OR FAULTS NOTED