As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT, PAX NOTED AN ELECTRICAL BURNING ODOR (NO SMOKE); ALSO NOTED BY THE FLIGHT CREW. CREW DEACTIVATED THE INTERIOR MASTER SWITCH AND NOTED THE ODOR DISSIPATED. AFTER LANDING SAFELY, CREW OPERATED THE INTERIOR MASTER SWITCH WITH THE APU RUNNING AND NOTED SMOKE EMANATING FROM AN AREA NEAR THE READING LIGHTS. MX FOUND THE SMOKE TO BE COMING FROM THE AFT ACM. THE ACM WAS REPLACED.