Question new build no power

[white.a.drew]

Okay so here is a odd one, I am building a pc for my brothers friend. We have already rma'd his psu and mobo for doa's. However new psu came in is working fine, but new build still wont turn on at all. Incase power button has a light. Bench building "just mobo cpu "with heatsink" ram and 24pin plus 8pin cpu power. Jump power jumpers and still get nothing. Another doa mobo?

 

[heshclub7]

PSU, mobo, cpu, Ram specs please

 

[white.a.drew]

Evga 750 b3
Msi b350 tomahawk
Cpu ryzen7 1600x
Ram Vengence ddr4 3000mhz