What was found
AIRCRAFT WAS GROUNDED: DURING FLIGHT, THERE WAS A BURNING ELECTRICAL SMELL STARTING AT ROW 5, BEHIND FIRST CLASS. THE SMELL GREW IN INTENSITY AND COVERED ROWS 5-13. PASSENGERS AND ALL FLIGHT ATTENDANTS SMELLED THE ODOR. AFTER DIRECTION FROM MAINTENANCE, CIRCUIT BREAKERS MCU1 ANDMCU 2 IN THE CEILING BY FIRST CLASS GALLEY WERE PULLED. ALMOST IMMEDIATELY THE SMELL DISAPPEARED. THERE WAS NO SMELL FOR THE DURATION OF THE FLIGHT. MAINTENANCE REPLACED SEAT ROW IN SEAT POWER SUPPLY UNIT PER AMM 25-21-38 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK WITH NO DEFECTS OR ODORS NOTED.