What was found
FLIGHT 3355, CREW REPORTED THEY NOTICED AN ODOR NEAR THE COCKPIT AND GALLEY. THE FLIGHT ATTENDANT TURNED OFF LIGHTS AND COFFEEMAKER AND THE ODOR DISAPPEARED. AIRCRAFT REMOVED FROM SERVICE. FOUND SIDEWALL BALLAST ON ROW 18BC SMELLING BURNED. REMOVED AND REPLACED BALLAST IAW EO EM 3300-026 STEP 1-4, STEP 10,11 AND 13. AIRCRAFT RETURNED TO SERVICE.