Lenovo T400 fails POST

[mlefe]

Dear all,
I have a T400 that turns on, briefly displays the boot up screen and suddenly shuts off without beeping. I've checked during the time that's on and, as far as I can see, all voltages (including VCCCPUCORE) are present.
Quite strangely, if I press on the VGA chip while it's booting, the screen keeps turn on longer but never completes/passes POST nor it shows nothing different.
At this point I'm inclined to think that there's an issue with the BIOS chip or the VGA one, but I'm not sure how to diagnose them.
What will you suggest?

Thanks!

[vaualbus]

Just do not lose your time here and take the pc to a repair center.
This is 100% cold solder joint under the cpu/gpu bga chip so without a solder station is very very hard to resolve the problem.
Sorry for the "bad" news.

[Smith]

you can do a basic repair with a hot air gun, or in an oven, but even if you get it working again it will stay a weak spot. I have done some with a hot air gun, and they still work, except for one. I made the mistake of playing a simple game, and it quit working within minutes. I did a second repair, but it had problems some weeks later.

Under normal operation, it can last quite some time, but you have to keep it cool (no heavy 3D work or games), and do not restrict the cooling fans.

[mlefe]

I feared that much... I do have a hot air station, so I guess this will become my first victim/try at reballing a VGA... I'm doing it for the sake of learning and It's not a big loss if it doesn't work.
I guess if I really want to play with this I'll have to buy a stencil/solder balls and don't count on simple air to do the trick, right?

[mlefe]

Also related to this: how can I know that it's a cold joint and not a fried chip? Is it the fact that's able to show something?
Thanks!

[Rasz]

replacement motherboard should be <$50, probably closer to $20