system turns on but immediately off when pcie power cables connected

[andreishut]

Hello! I spent the most of today trying to troubleshoot an issue with a new system i assembled this morning. This issue is when the gpu power cables are connected to the psu, the system wont boot. It sort of turns on and the psu fan spins half a revolution and the LED on the mobo flashes but then it instantly shuts off again. I have not yet assembled the rig into a case so i have been powering on the system using a screwdriver to the power button pins.

 

I first got the issue this morning when i assembled the rig with everything in place and connected, expecting things to go smoothly like they have done in the past. However upon first boot attempt the issue first showed. I at first thought i had broken something, maybe even shorted a connection and possibly destroyed a component but i dont think that is the case. I tried all sorts of things: i checked connections, changed the power lead, changed the power outlet i was using, but nothing seemed to work. A friend recommended i tested the psu using the paperclip method so i did, and found that it turned on and ran no problem, following this i took out the motherboard and set it up on the box it came in and booted it up on there with no problems. It booted, fans were spinning and everything, however i did not plug in a display to test for video output. I then plugged in the gpu's and tried booting again and the same issue happened. I then tried with one gpu thinking it could have been too much power? (which was unlikely because the psu is 1200w) Sadly it still didnt boot. So i unplugged the gpu power connectors from the gpu but left them connected to the psu and the same issue. Later on i somehow thought i had fixed the problem as it booted with the gpu plugged in but then realised it was just plugged in by the pcie connector via the motherboard. So im beginning to think it might be a cable issue? I dont have any spares to test this theory however it happens on both the cards ive tested. I even began thinking there might be a particular order i need to plug things into the back of psu as i was willing to try anything at this point.

 

Any kind of help or advice would be massively appreciated!

 

 

PC specs:

CPU: i3-9100F

RAM: Corsair 8GB DDR4 LPX 2133Mhz (dual channel)

PSU: Corsair AX1200 ATX PSU 80+ Gold

MOBO: MSI Z390-A PRO

SSD: Kingston 120gb

GPU1: Gigabyte Radeon RX 5700 XT Gaming OC 8G

GPU2: MSI Radeon RX 5700 XT 8GB GAMING X

(using powered risers as this was meant to be a mining setup however i tried without and the same thing was happening)

 

 

 

[andreishut]

I resolved the issue. The power cables coming out of the psu have to be in a certain orientation. Its now booting.

[Juch]

Couple clarification things:

 

Sorry are you using 2  gpus in crossfire? or u tested it with a second gpu to see if the first one was dead?

 

 

I doubt you are since ur cpu is an i3 but if so:

If you are using 2 gpus in crossfire, you need to have a crossfire MB. Also if so you might need a bridge to connect the two together.

 

You could also have a short some where in the system, I think you are using a test bench/building out out of the case first, (smart) since it "kinda turns on" you might have a contact that touches metal that contacts ground, this then would cause a short/unusual power delivery, so the motherboard/psu shuts of to avoid bricking components.

 

When you set it up on the MB box, did you plug in the gpus? or one?

Try this again for both gpus one at a time, and PLUG IN a monitor to the GPU's since the cpu doesn't have integrated graphics. See if it outputs to a display, if not try the other gpu.

 

Also did the MB beep at all? or did you install a little speaker that came in the MB box (specifically for beep codes)

 

 

 

 

[Juch]

8 minutes ago, andreishut said:

I resolved the issue. The power cables coming out of the psu have to be in a certain orientation. Its now booting.

lol great!