What was found
CREW REPORTED SMOKE IN THE CABIN. THE AIRCRAFT DIVERTED AND LANDED WITHOUT INCIDENT. MAINTENANCE PERFORMED ENGINE, APU, AND PACK CHECKS WITH NO DEFECTS NOTED, CABIN INSPECTION REVEALED INOPERATIVE SIDEWALL LIGHTS AT SEATS 5A & 20A. MAINTENANCE DISCONNECTED THE AFFECTED BALLASTS. MAINTENANCE REMOVED AND REPLACED THE LIGHT BALLASTS, OPS TESTED WITH NO DIFECTES NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.