As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED A STRONG BURNING SMELL IN THE COCKPIT AND CABIN. THE ACFT RETURNED TO DEPARTURE WHERE IT LANDED WITHOUT INCIDENT. MX INSPECTED THE ACFT AND R & R THE LIGHTING BALLAST ABOVE ROW 1A, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.