What was found
DFW - FLT 641 - EN ROUTE DFW-YYC, SHORTLY AFTER TAKEOFF, SMOKE WAS REPORTED IN CABIN. EMERGENCY DECLARED, RETURNED DFW AND LANDED WITHOUT INCIDENT. REPLACED RIGHT PACK PRIMARY AND SECONDARY HEAT EXCHANGER. REPLACED APU, AND ACCOMPLISHED PACK BURN OUT. NO SMOKE OR ODORS. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)