Nintendo 3DS XL charges but does not power on

Hi!

I recently bought a Nintendo 3DS XL that was said to be broken with and idea in mind that I’ll repair it and use. It was not booting up, when power was hit the blue LED light up, bottom screen flashed for a moment and then I hear a popping sound - device turns off after that. I looked online and it was said that most likely it is a broken flex cable connecting the speakers.

When I opened up a console I saw that it was water damaged and some corrosion happened on flex cable connectors so I cleaned them up with IPA and tried to turn it on again - same results as before. I then ordered a new flex cable and with a lot of struggle I managed to replace it.

I put everything together, close it up and try to power it on again and boom! It won’t boot up, but not like before - it does not even light any of the LEDs. When a charger is plugged in, orange LED lights up, but when I click a power button it turns off and lights up again.

I thought that maybe I did something wrong and damaged something more so I disconnected a speaker ribbon cable and tried to boot it up again. It did the same thing as before I replaced the cable - blue LED pops up, screen flashes for a second and it turns off - this time without a popping sound (as expected, hard to make a sound without speakers).

I checked a battery voltage and fuses on the way and they are OK.

Do you guys have any idea what could go wrong? Is the not powering on problem related somehow to a flex cable replacement? Or maybe this new problem is not related and the 3DS XL’s booting process goes further then before and stops somewhere else?