Question Pc turns on for a second then shuts off

[Vyom Sharma]

I just built a new pc the specs are given below. Whenever I plug it in and turn on the power supply, all the LEDs light up for half a second but then shut off. I have checked all the internal connections. Also the pc isn't connected to a display yet, does that effect this?
i7- 9700k
Evga rtx 2070 black xc
Cooler master masterwatt 750w
Cooler master ml120 rgb
Corsair crystal 570x

 

[alexoiu]

What motherboard? Try testing with case fans disconnected.

 

[Vyom Sharma]

Gigabyte aorus pro wifi

 

[alexoiu]

Have you tested with no case fans connected?
If yes, and still the same, try testing the board outside the case.

 

[Vyom Sharma]

How?

 

[alexoiu]

Remove the board from case, put it on its box, connect the 24 and 8 pin power cables, leave CPU and CPU cooler only, start the board and see if the fan does spin.