What was found
FLIGHT 1756, CMH TO PHL - ON CLIMB THRU FL200 THERE WAS A STRONG SMELL OF SMOKE IN THE CABIN. PACK NR 1 SUBSEQUENT FAILED, SMOKE SMELL DISSIPATED AFTER SELECTED OFF. MAINTENANCE FOUND AMBER X ON EICAS PAGE. TRIED TO OPERATE PACK NR 1, PACK FAILED AGAIN WITH SMOKE SMELL IN CABIN. RELEASED PACK NR 1 PER MEL. PACK NR 1 SWITCH IS OFF, A/C IS OK FOR SERVICE. REMOVED AND REPLACED NR 1 AIR CYCLE MACHINE. OPERATIONAL CHECK IS GOOD PER AMM 21-51-00, THIS CLEARS MEL.