As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LHR - FLIGHT ATTENDANT REPORTED SMELL OF BURNING WIRES NEAR SEAT 13G. SMELL DISSIPATED AFTER ELECTRIC POWER REMOVED FROM VIDEO SYSTEM AND RECIRCULATION FANS TURNED OFF. FLIGHT LANDED LHR WITHOUT INCIDENT. SEATS 12 E AND G AUDIO VIDEO UNIT FOUND WITH FAN FAILURE. REPLACED AUDIO VIDEO UNIT. SYSTEM GROUND CHECK NORMAL OPERATION.