Backlight Can’t Be Turned On - Acer LCD-S243HL Service Manual

2. Backlight can't be turned on
No raster?
Yes
LED orange?
Yes
Backlight can't
be turned on.
Yes
Is there 19V
voltage on pin23
of IC501,IC503
Yes
Is there high-level voltage
on pin1of IC501,IC503?
Yes
Are CN511 and CN512
connected rightly?
Yes
Is Pin24 of IC501,IC503(VREF) 5V?
Yes
Is ok L501,L502?
Check feedback circuit
No
Check adapter
No
Is R501 OK?
No
No
No
Yes
Yes
No
Is IC501,IC503 ok?
No
Check I/F
board
R501open
Connecting the
output connector
again
IC501,IC503 fail
L501,L502 fail
END