X399 Aorus Xtreme wont post/troubleshooting.

[Pesky Ngon]

got this board broken on the used market. it had some bent pins which I sorted out, but it seems that isn't the only issue. when the power supply is switched on, the clear CMOS and power buttons on the rear IO light up, but if I press either button the board immediately turns off and the lights go out. I don't even get a post code. this happens on both bios switches, with or without a CPU installed. 

 

has anyone got any suggestions on what I could try to get this thing working? I've tried to repair a few boards in the past but have never seen this sort of problem. would very much appreciate any advice you might have.