Sony A1E Series Service Manual page 45

FLOW
7. LIGHT SENSOR ERROR
Backlight level does not change
when ambient light changed
Check UI setting and make
sure light sensor setting is
"ON"
Setting issue
Change setting to "ON"
Resistor value
[BKA]
R253 : 0 [ohm]
R240 : 150k [ohm]
XBR-55/65/77A1E
Setting is "ON"
Setting is "OFF"
Check harness connection OK
between BKA board and
Smart Core
NG
OK
Check harness connection
between BKA board and H-
board
NG
OK
Change harness between
BKA board to Smart Core
harness
NG
OK
Change Smart Core
NG
NG
Check resistor value on BKA
board
OK
TROUBLE SHOOTING
Battery of remote commander
could be weak.
Change battery.
Harness connection
issue
BKA board to Smart Core harness
issue
Smart Core issue
Parts issue
Change BKA board
Main device issue
45