What was found
(CAN) CABIN CREW REPORTED 'PASSENGER READING LIGHT NOT WORKING IN Y CLASS.' THE 1ST OBSERVATION BY MAINT NOTED THAT IN CENTER SECTION OF AFT CABIN, ROWS 19DEF TO 36DEF, CALL LIGHT ILLUMINATED AT SEAT 36DEF, 26DEF & APPROXAMITELY ROW 20 OR 21DEF. CALL LIGHT AT SEAT 26DEF UNUSUAL ORANGE COLOR. PSU SEAT ROW 26DEF INDICATED EVIDENCE OF EXTREME FAILURE AS INDICATED BY SMOKE REMAINS ON & AROUND PAX SERVICE UNIT DECODER (PSUD). A/C WIRING CONNECTOR PINS 2 & 3 TO PSUD J2 CONNECTOR WERE BURNED. NO EVIDENCE OF PIN OR SOCKET CONTACTS REMAINED REPLACED PSUD AT ROW 26DEF & CONNECTOR. ALSO CHANGED AREA SERVICE BOX & THE PSUD AT 27DEF.