As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT HAD FLOWN SEVEN LEGS WITHOUT KNOWN INCIDENT. PILOT REPORTED EN ROUTE. THERE WAS A BURNING ODOR COMING FROM ROW 1. AIRCRAFT MAINTENANCE REMOVED AND REPLACED THE PASSENGER SERVICE UNIT (PSU) AND NO FURTHER ODOR WAS DETECTED. ACFT RETURNED TO SERVICE.