What was found
CABIN SMOKE SEEMED TO ORIGINATE AROUND 3L. POSSIBLE ASH/OIL RESIDUE AT ROWS 36-37 CDE CENTER OVERHEAD PANEL. REMOVED CEILING PANELS AND INSPECTED BALLASTS, WIRING, PSU'S ETC. FOUND GASPER AIR DUCT PULLED LOOSE AT 37 CDE. SECURED DUCT. RAN ALL ELECTRICAL SYSTEMS, PNEUMATIC SYSTEMS, AND ENGINES. NO FURTHER TROUBLE FOUND.