New build woes

Long time lurker, 1stish time poster. I just built a 1600x system with b350f strix, cx550, h60, and corsair vengeance ram with a rx580. When the psu is switched on, the rgb under the strix logo lights up, as does the orange led on the bottom right of the mobo. No error lights come on, no cpu fan, no case fans (molex). Tried shorting power button pins to try and eliminate id10t error. Tried with nothing connected except cpu and ram, cpu and 1 stick of ram. Reseated cpu, no bent pins, Reseated 8pin and 24 pin power as well as cpu fan and pump fan. No joy. I wanted to try and test psu with a molex fan, but all of the wires are black and I don’t know which ones to short. Any advice is welcome because at this point I’m ready to pick up a psu and try another before I rma the board and psu

It’s already there two on a 24pin atx

Is the PSU used?

Just to clarify, you get LEDs but no power on?

Also triple check you’re shorting the correct pins on your mobo

Brand new psu, led come on as soon as psu is switched on. I must have checked the pins 30 times before I shorted them lol. I will check the psu in 12 hours or so when I get out of work.

Psu will happily power 4 miles fans with no issue
Edit. To clarify only rog rgb led and one orange led on bottom right of mobo come on, and they come on as soon as psu is switched on