5-10 Back Light
Backlight does not work
LCD BACKLIGHT
U305 pin 7 210~230 VAC ?
Yes
LCD backlight on ?
Yes
END
Flow chart of trouble shooting
Backlight "ON" mode
in the menu?
Yes
Between R306 and
R310 = "H" ?
Yes
No
No
Resolder CON1 pin 37, 38
Resolder R310, R309
Resolder Q302
Resolder J403
or Replace Key PCB
No
Select backlight "ON" mode
No
GPO1 by test S/W
KEY PCB LED
Check the
L300, U305, R306, Q301,
C314, C315, C316
or Replace EL sheet
No
No
No
Q302 pin 2 = "H" ?
Yes
Q302 pin 3 = "L" ?
Yes
Key PCB LED on ?
Yes
END
5-10