What was found
ORD - CREW REPORTED A BURNING SMELL IN THE CABIN. IN-FLIGHT ENTERTAINMENT SYSTEM WAS DEACTIVATED AND NO CHANGE NOTED. AUXILIARY POWER UNIT WAS TURNED OFF AND NO CHANGE NOTED. EMERGENCY DECLARED, RETURNED ORD WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND PLASTIC MELTED ON HOT PLATE OF COFFEEMAKER ON LEFT SIDE OF AFT CABIN. ALL OTHER PARAMETERS CHECKED AND NO FURTHER ODORS NOTED. SYSTEM GROUND CHECK NORMAL OPERATION.