Take a look over
http://rapidshare.com/files/17804484...NT_PLACING.pdf and check/change V4200 / L4201 / V4201 - this is a group that make LCD backlight - LCD backligh is wired to pins 22 and 24 on X4200... ( Sometime is possible to have broken lines for LCD backlight on LCD flex cable - on this place that cable is wraped - so you can check it first ) ...
Write me result.
WBR, DebeliaMark, BG