What was found
EWR - FLT 1223 - DURING TAKEOFF FROM EWR, SLIGHT SMOKE NOTED IN CABIN. TURNED OFF BOTH AIR CONDITIONING PACKS AND SMOKE CLEARED. AIRCRAFT RETURNED TO EWR AND LANDED OVERWEIGHT WITHOUT INCIDENT. REPLACED APU DUE TO OIL LEAKAGE. ACCOMPLISHED PNEUMATIC SYSTEM DUCT BURN-OUT PROCEDURE. SYSTEM LEAK AND GROUND CHECKED NORMAL OPERATION WITH NO SMOKE OR SMELL NOTED. ACCOMPLISHED OVERWEIGHT LANDING INSPECTION WITH NO DEFECTS FOUND. ACCOMPLISHED FUNCTIONAL CHECK FLIGHT WITH NO DEFECTS FOUND. SYSTEM OPERATIONAL CHECKED NORMAL. (X)