Hi.
Dell Vostro 5120 brought for Not booting Problem(with LCD 15.4" Hitachi TX39D89VC1FAA assembled) after problem solved( Reballing 630-U2) now we have display but background is Pink, LCD tested on other one and Still pink!!, another LCD assembled on Laptop and display is fine. How knows why background goes pink and how to fix it?

CCFL lamp dies

PS
>Reballing 630-U2

it doesn`t repair

U mean Can not repair 630-U2 by rebelling?

Yes. Trouble with contacts between crystal and chip substrate. After reballing (high temperature) contacts are restoring for a short time.... usually a few weeks.

+
in this case need check lamp in display and change lamp/display

It could be a issue in the screen conector. Lack of a RGB channel could cause this effect.



Yes, totally agree. In some cases you will see some strange effects after reball, like high VGA temperature, this will indicates that the failure is inminent.

after changing Flour-cent Lamp nothing changed.

As I understood early message ("LCD tested on other one and Still pink!!, another LCD assembled on Laptop and display is fine") the other LCD screen works fine on this laptop.
Change screen? It`s easier ) If not - check resistance LVDS pairs (screen connector: pins 8,9,11,12,14,15), must be same, "update" edid

Problem from LCD Board. SO it is better to renew whole LCD.