As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - DURING PREFLIGHT INSPECTION THE CREW REPORTED A BURNING SMELL AT ROW 4. MAINTENANCE INSPECTED THE AIRCRAFT AND REMOVED AND REPLACED CEILING LIGHT BALLAST, OPERATIONALLY TESTED WITH NO DEFECTS. THE AIRCRAFT WAS APPROVED OF RETURN TO SERVICE.