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 ELECTRICAL BURNING ODOR IN THE COCKPIT AND CABIN WITH VISIBLE SMOKE IN THE COCKPIT WITH EVIDENCE OF AN APU FIRE. MAINTENANCE INSPECTED THE ACFT, FOUND NO EVIDENCE OF APU FIRE OR DAMAGE, FURTHER INSPECTION FOUND THE APU STARTER GENERATOR TO BE THE CAUSE OF THE SMOKE AND ODOR. THE STARTER GENERATOR WAS R & R, OPS TESTED WITH NO DEFECTS, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.