Sony XBR-55X850D Service Manual page 57

FLOW
5. KEY SWITCH BUTTONS ERROR
Side key buttons error
Resistor value
[BMFW2/BM1]
R1089 : 0 [ohm]
R1086 : 47k [ohm]
R1432 : 4.7k [ohm]
* R1089 may be not mounted
Resistor value
[BMFW2/BM1]
R1042 : 4.7k [ohm]
R1091 : 0 [ohm]
R1087 : 20k [ohm]
R1088 : 22k [ohm]
* R1091 may be not mounted
XBR-55X850D/855D/857D, 65X850D/855D/857D, 75X850D/855D/857D
Check harness connection
between B-board and
switch module
NG
Change harness between
B-board to switch module
harness
NG
Change switch module
NG
Check resistor value on B-
board
OK In case that power key error
Check resistor value on B-
board
In case that buttons error except power key
OK
OK
Harness connection issue
OK
B-board to switch module
harness issue
OK
Switch module issue
NG
Parts issue
NG
Main device issue
Change B-board
TROUBLE SHOOTING
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