When I plug in my Xbox fan immediately starts spinning full speed

I have an Xbox one fat purchased back in 2014.

Once in 2019 the power supply broke down, and I replaced it with a pc power supply.

It worked great until the other day I left the console to work and when I got back to the TV there was a black screen and the console was not turning on at all.

I left it for a while and tried it again pluged it in and the fan started spinning at full speed immediately nothing else worked.

I disassembled the console to the motherboard, and checked the power connector for shorts as I've seen on YouTube and it seems that everything is fine also checked the mosfets next to the APU and it was fine too. I tested the test point TP4B1 witch is for 5 volts and there was noting. Checked U3C2 chip it was also fine.

I don't know what to do next if someone has any idea what to do feel free to suggest.

Sorry for my English not my first language :)