What was found
CREW REPORTED SMOKE IN CABIN. MX INSP ACFT & FOUND SMOKE COMING FROM SHORTED WIRES JUST BEHIND WALL IN AFT CARGO BAY. FOUND OUTFLOW VALVE DC MOTOR BAD. MX R & R OUTFLOW VALVE. DAMAGED WIRING REPAIRED IAW MM & WIRING DIAGRAM. CABIN PRESSURE CONTROLLER REPLACED FOR POPPING DC MOTOR C/B AND HEATER C/B. OVERHEAD PRESSURE CONTROL PANEL ALSO REPLACED FOR PRECAUTIONARY REASONS IAW MM. OPS CHKS GOOD. TEAR DOWN REPORT OF OUTFLOW VALVE SHOWS AC MOTOR & GEARBOX NOISY & SLUGHISH, SAME WITH DC MOTOR. BEARING FOUND DRY & BINDING. UNIT OVERHAULED IAW CMM, TEAR DOWN OF PRESSURE CONTROLLER SHOWS SHORTED COMPONENTS. UNIT REPAIRED IAW CMM. TEAR DOWN OF PRESSURE CONTROL PANEL SHOWS NO FAULTS. UNIT TESTED IAW CMM.