What was found
ABOUT 3+15 INTO THE FLIGHT FA'S NOTICED SMOKE COMING FROM LT SIDE OF AIRCRAFT UPPER SIDE WALL ROWS 15-16-17 RAN PROCEDURE 4-8-1-1 CABIN LIGHTING SMOKE, FIRE AND PULLED ALL C/B'S IN MID-GALLEY SERVICE AREA ALL BREAKERS PULLED TO HELP ISOLATE THE SOURCE OF SMOKE. FOUND PROBLEM WAS DECODER FAILURE ISOLATED TO THE FOLLOWING SEATS LT SIDE OB SEATS 12-14-15-16-17 ABC. REPLACED OVERHEAD DECODERS ROWS 12-14-15-16 IAW MM 23-33 P/N RD-AX5321 S/N 104079, 103990, 106855, 100376. INSPECTED WIRING NO DAMAGE NOTED IN OVERHEAD AREA. CHECKED O2 SYSTEM IAW MM 23-33.