Sony KD-75X7800F Service Manual page 63

5.0 Key Switch Buttons Error
Side key buttons error
Check harness
OK
connection between B-
board and switch
module
NG
Change harness
OK
between B-board to
switch module
harness
NG
OK
Change switch module
NG
Main device issue
Change B-board
Harness connection issue
B-board to switch module
harness issue
Switch module issue
63
SYS SET