The motherboard does not start with a new PSU, why?

Question

ASUS

Good afternoon. I got myself a new PC and there was a problem with the assembly. The motherboard starts only from the old PSU, on the new one the coolers twitch for a moment and immediately click and the protection (probably) works on the PSU. The bp itself is working, I checked it with a paper clip and connected it to the old assembly - everything starts up. What could be the problem? On the motherboard, plus everything, I accidentally bent a couple of legs on the socket during tests and they don’t accept it in the service one, the cpu fan also behaves strangely - we connect it to the end - it doesn’t work, we disconnect it almost completely (on snot) - it spins.

Mother - Asus z490-a, bp - deepcool dq850

Answer 1

There are two options.
Either when installing the mother, something shorted on the case - that's when the power is turned on and the protection works.
Or a pair of legs that were bent by such a "successful" one that is responsible for the power supply :)