What was found
DURING DESCENT, A STRONG BURNING SMELL EMITTED IN THE FLIGHT DECK AND BEHIND DOOR 1L FOLLOWED BY A MASTER FIRE WARNING AND BELL. PULLED ESSENTIAL TRANSFORMER RECTIFIER CIRCUIT BREAKER, DECLARED AN EMERGENCY, AND LANDED THE AIRCRAFT WITHOUT FURTHER INCIDENT. REPLACED THE TRANSFORMER RECTIFIER UNIT, FIRE DETECTION CONTROL ELECTRONICS MODULE WITH CARDS, MAIN AIRCRAFT BATTERY AND BATTERY CHARGER, A-13 CARD IN THE MASTER DIM AND TEST MODULE, AND REPAIRED THE MAIN BATTERY OVERHEAT TEMP SENSOR WIRE. OPERATIONAL CHECK GOOD.