[SOLVED] Computer keeps turning on and off

[quantran1101]

Hi all,

I recently built a new PC with:

• ASRock Z390 Pro4
• I5-9600k
• Gigabyte Nvidia RTX 2070
• Phanteks P400s case.
• Thermaltake 750W PSU.

(The full list is in here).

I assembled everything, plugged in and everything went well, I can do everything on the computer. However I noticed that the case fans weren't running, so I took it apart and took another look and found out that one of the case fans' cables wasn't plugged into anything, and one of them were plugged in this thing which is connected to the front panel:

There are 2 pins (for 4 open spaces/4 possible pins) in each. I disconnected the case fan's cable and plugged both in the motherboard. However, now the computer is not starting up - after the power button is pressed, it will turn on for 1 second then off immediately, and repeat until I turn off the PSU or hold down the power button.

While figuring the case fans out I was also touch the other parts of the motherboard, and found out that I forgot a screw for the motherboard, so I put that it.

I have taken the PC apart - I took the video card out, unplugged everything from the motherboard, removed the motherboard from the case, removed RAMs and the SSD (so everything except for the CPU and CPU cooler since I was worried about the thermal paste which I used up). Then I put everything back together, put the motherboard in the case, plugged everything in and tried running again. I don't know if there's a problem with the PSU but I don't know how to troubleshoot, it was fine before though.

What could be the problem here?

 

[Lutfij]

You might want to detail how you connected the fans to the PSU/fan hub/splitter and how the rest of the wires are managed in your case. To me it looks like you've connected something in the wrong order or that the cable is shorting the entire system with the wire being snagged onto a bare soldering point between the (underside of the)motherboard and the motherboard tray.

You might want to breadboard the system and see if the issue persists.

 

[pcherry5]

Hey now. I had similar problem and found that my memory module was not properly seated. Happened 2X on 2 different Dell computers. "Click is set" is a good sound.