Fujitsu Siemens AMILO L7310GW dead but not quite?

[the_jazz]

Hello,

I have pulled out my hair over this one for so long, couldn`t find the answer.
Practically i have good experience with disassembling laptops, soldering, changing parts and so on. But this one is over my head!

So, a friend of mine gave me his AMILO L7310GW notebook with a power problem. Laptop powers on, you can hear the fan spinning for 5 seconds and then powers off again. Than again, powers on (by itself), 5 seconds spinning (no post no nothing) and powers off. Infinite loop until i plug it out of the power adapter. Since my friend used his laptop (when it was still working) on a lan cable, so, i thought that the integrated lan card may be blown out and creating a short circuit on the motherboard. I disassembled it, soldered out the lan chip - no change at all. Soldered out the bios chip, put it on a programmer, put on fresh new (last) bios - still no change. Tried swapping ram, different power adapter (same voltage), hard drive, CPU, everything i could think of. Also done BGA reballing on the VIA video chip, and VIA chipset.

So after a month and so - nothing seems to be changing the picture. Infinite power on/off loop. I`m pretty sure that this is major problem, but i had to try here :)

Any ideas how to make it work?
Thanks

[caperjack]

Infinite power on/off loop

i have seen this fixed by simply re-installing windows

[the_jazz]

This would be the simpliest thing to do, but...only if the notebook really gets to loading OS (which it does not). The infinite power loop is in the beginning (before post screen, before everything). I never reach loading OS.

Any other ideas?

[caperjack]

no sorry ,by the look at what you did already to try and fix it you know about laptops that I ,sorry