What was found
WHILE DESCENDING THRU 7000 FT, HAD BURNING RUBBER SMELL AND ACRID FUMES IN THE FWD CABIN AREA AND THE COCKPIT. INITIALLY SUSPECTED THERAPUETIC O2 CYCLINDER TO BE REASON FOR BURNING RUBBER SMELL. THERAPUETIC O2 BOTTLE WAS REMOVED. THE PSUS, SIDEWALL PANELS, O2 GENERATORS, UNDERSEATS. NO DEFECTS FOUND. OPERATED CABIN LIGHTS, VIDEO, GALLEY EQUIPMENT, RAN BOTH ENGINES AND OPERATED PACKS. NO DEFECTS FOUND. ACCOMPLISHED CIDS TEST ON PTP - NO DEFECTS FOUND. WHEN AN O2 BOTTLE IS FIRED IT BECOMES COLD. COULD NOT DUPLICATE BURNING RUBBER ODOR.