Xbox One turning off after a couple of seconds

Hi,

Recently I got myself an original Xbox One (the fat one). Unfortunately, it won't work. I press the button and it tries to power up, even the fan starts to turn but after a couple of seconds, it dies.

My observation is that if I try to turn it back on again right away it dies within a second but if I let it a couple of minutes to rest, after pressing the button it tries for a couple of seconds longer before dying.

I assume that the power brick is fine because it shows proper LEDs, I also bought it separately so it's not a part of this faulty set.

Have you got any ideas about, what can I do to fix that Xbox? I'm not afraid of soldering and even changing capacitors but currently, I'm out of ideas.

Thank you in advance follows!