Hi. I have a problem with K50AB laptop (platform rev 2.1). After replace bga chip (north bridge 4026) laptop gives red screen (for example on start instead black screen under Asus logo screen is red). Bga is new (2013). Firstly laptop had a black screen (nothing on it). What can be dameged? Laptop have also graphic (8014). Could it be graphic bga chip?

P.S. sorry for my english.

Try to reball it

I'm already changing this gpu to new and i will give response soon what happened. Red screen is on both graphic setiings in BIOS (internal and external)...

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Posted after 1 hour 14 minutes 16 seconds:
After replace gpu problem still is the same... red screen... Should I try to change for old bga chip 4026 or is something else which can make this problem? Anyone?

How you determined what problem in GPU?

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Jak było określano, że problem jest w GPU?

Based on cpu testing tool (which shows connections between CPU and North Bridge). It shows that this is a problem with North Bridge.

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Podstawka procesora pokazywała problem w komunikacji pomiędzy CPU a mostem północnym stąd wymieniałem most północny.

If is not a problem with GPU could be a problem with the PCB layers. I hope not.

Good Luck

What else can be responsable for this "red screen"? Is someone have a schematic diagram (K40AB rev 2.1)? I would be very gratefull :)

Can you plug in external monitor to the laptop?

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Czy jest możliwość podłączyć monitor do laptopa?
Schematę można pobrać tutaj
http://zremcom.ru/scheme/scheme-asus/fi ... s-k40aa-ab

show photo of the North bridge on the motherboard. Can elements of the demolished near the North bridge. Scheme on K40ab for your mail.

On external monitor everything was fine. Thanks for scheme, It helps. Problem solved! I replaced TS3DV416DGGR (texas instruments) smd on U7801 field and everything is fine on internal and external screen :) Thanks everyone for help!

I think it was a based problem with U7801, not the graphic controller, great jobs, i haved same problem with customer notebook, but i have blank screen, Your solution, reasolved also my problem. Thx .