What was found
PASSENGER REPORTED SMALL AMOUNT OF SMOKE CAME FRM UNDER SEAT2AD. AUDIO ENT SYS WENT INOP AFTER SEEING SMOKE. CREW TURNED OFF MASTER ENT SWITCHES AND PULLED C/BS TO ISOLATE ENT SYS SMOKE AND SMELL DISSIPATED. MTC FOUND SEAT ELEC UNIT UNDER SEAT 2A BURNED. DISCONNECTED CONNECTORS FRM SEU. TURNED OFF AUDIO/VIDEO MASTER SWITCHES AND PULLED ENT C/BS TO ISOLATE PASS ENT SYS. FWD TO MCO AND PLAC. REPLACED 2A SEB AND CABLE ASSEMBLY FROM 1A TO 2A. POWER TO RIGHT SIDE ENTERTAINMENT SYSTEM CHECKS GOOD. MCO/PLAC REMOVED.