As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, SMOKE IN CABIN WAS REPORTED COMING FROM UNDER SEAT 20D. EMERGENCY DECLARED. LANDING UNEVENTFUL, AIRCRAFT WAS GROUNDED. MAINTENANCE FOUND IN FLIGHT ENTERTAINMENT BOX UNDER SEAT 20D TO HAVE OVERHEATED. R & R THE SEAT ELECTRONICS BOX AT 19ABC IAW AMM 44-24-32. OPS CHECK NORMAL.