What was found
DURING CRUISE AT 41,000 FT, A BURNING SMELL WAS NOTICED IN THE FLIGHT DECK. LEAD FLIGHT ATTENDANT REPORTED SMOKE IN THE CABIN. SMOKE IN THE AIRCRAFT DISSIPATED AFTER SMOKE CHECK LIST WAS COMPLIED WITH BUT RETURNED DURING APPROACH. MAINTENANCE CHECKED OPERATION OF OVENS, COFFEEMAKERS, HOT PLATES, INTERIOR LIGHTS, LAV HOT WATER HEATERS, LAV FLUSH MOTORS, AND RECIRCULATION FANS. CHECKED E/E COMPARTMENTS, AND CB PANELS. PERFORMED ENGINE HIGH POWER RUNUP AND OPERATED PACKS. APU CHECKED OK. NO TROUBLE FOUND. AIRCRAFT RETURNED TO SERVICE.