ThinkPad T400 not booting

4 respostas [Última entrada]
Megver83
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Joined: 12/21/2015

hi everyone, I've a "ThickPad" T400 which I rescued and resurrected, but then it died again :'(
It didn't have anything, no battery, no BIOS battery, no DVD reader, no screws, and a bad flex (display cable). After fixing almost all that (now it has a bios battery, all the screws and a good flex, but I don't have the battery and the DVD reader), it somehow stopped working (just like you read). I turn it on and nothing it's shown, then it reboots, and at the 3th time it rebooted it used to work but now it powers off. I've tried everything, but nothing.

My questions are the following:
1) what the hell is happening?
2) could libreboot fix this? (it actually runs the default nonfree BIOS) it could be a BIOS issue maybe.
3) similar to 1, which diagnostics can I do it to discover the issue and fix it?

Magic Banana

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Joined: 07/24/2010

Maybe dust on top of the processor that makes it overheat automatically shutdown the computer?

Megver83
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Joined: 12/21/2015

could be, it is old and it was used to take pieces as spare parts, once I dissembled it completely (I had to take out a USB port because it was not working, it was destroyed), I don't discard the option of bad ventilation, I'll also apply some heatsink.

vita_cell
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Joined: 07/19/2015

Can be bad-cap (bad capacitor), or it shorts with something (I had this problem with x200t, heatsink was touching a diode). If it boots (or if it was booting), so the ram and all hardware is compatible.

When a computer works fine but shut-downs (or reboots), can be overheat or bad-cap (or bad-caps)(I attached iamges of electrolitic bad caps). If it boots and reboots or powers off, you have some power problem.

You can meter the capacitance and short of every capacitor, and if some one shots or has lower capacitance than expected, you should replace it with same or more volts and same or more capacitance capacitor.

First you must to tear off everything and inspect the motherboard for damages, shorts, bad caps, or if something is burnt...

cap_before.jpg FLj6n.jpg htrh.jpg
Megver83
Desconectado
Joined: 12/21/2015

thanks, any news I'll post them here
Could be a problem of energy, it has no battery but it worked with the charger only, it just turns on, and when it has to show up the BIOS start up screen, it reboots, and on the 3th time it shuts down