What was found
AFTER LANDING DURING ROLL OUT WE SMELLED AN ODOR THAT SMELLED LIKE SMOKE & HAD A DIRTY SOCK SMELL. WE HAD VISIBLE SMOKE IN CABIN. APU WAS NOT ON AT THIS TIME. DURING TAXI WHILE APU WAS BEING STARTED RECEIVED AN AMBER PACK TEMP HIGH MSG. ARRIVED AIRCRAFT & ATTEMPTED TO RUN APU. FELT NO AIR, NO AC. INSPECTED EXTERNAL APU DURING OPERATION, DIDN'T FEEL COLD ON ANY APU LINES. PERFORMED T/S FOR AMBER PACK HI TEMP MSG. DIRECTED TO REPLACE ACM. REMOVED ACM & PERFORMED UNSUCCESSFUL TORQUE CHECK PER MCC REQUEST AND REPLACED ACM IAW AMM 21-52-13-000-801. PERFORMED SUCCESSFUL OPERATIONAL AND LEAK CHECKS IAW AMM 21-52-00-710-801 AND 36-11-00-790-801. RESPECTIVELY. RESTORED AIRCRAFT TO ORIGINAL CONFIGURATION.