As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3663, CREW REPORTED SMOKE IN THE CABIN, PASSENGERS CONFIRMED VISIBLE SMOKE. AIRCRAFT REMOVED FROM SERVICE. GROUND RAN AIRCRAFT IN VARIOUS POWER CONFIGURATIONS USING BOTH ENGINE AND APU BLEEDS TO SUPPLY PACKS. INSPECTED ACM AREA. POSITIONED AIRCRAFT IN DIFFERENT HEADINGS WITH RESPECT TO WIND. COULD NOT DUPLICATE, SMOKE IN CABIN. AIRCRAFT RETURN TO SERVICE.