Question CPU Wont Boot

Oct 11, 2019
Hello all,

I have done a search of the forums for this problem and it seems to be a common consensus that the MOBO is the issue. I just want to double check before I drop another $300 that this is the problem.

Built my computer with the following
Aorus X570 Pro Wifi
AMD Ryzen 7 3800x 8-core
Corsair RM-750x
Radeon RX 5700 XT
2x Ripjaws 16GB
Samsung 970 Evo 500GB

I hooked everything up and the computer worked fine. I kept the old BOIS (I think one version old) and installed Windows 10. Everything worked fine for weeks. I would not shut down the computer just let it sleep when I was done. Well I did not use it for about 3 days and I went to start it up and nothing. No fan boot up, no LEDs, no noise, nothing. I started troubleshooting and found when I unplugged the ATX 12V 8-pin the fans, GPU, and LEDs would all light up as well as the MOBO CPU LED would light up. Then I tried using a different 8-pin connector and same results. Then I removed all the components except 1x RAM, CPU, and fans. Same results, when the 8-pin was hooked up nothing but when removed the the fans, LEDs, and MOBO CPU LED light. I even checked the CPU for bent pins and no thermal paste or thermal paste on the pins or MOBO and nothing. All the paste was on top of the CPU and just a small about on the sides but still essentially on the top of the CPU. I even removed the MOBO from the case to make sure a mounting bracket was not shorting anything. Still the same results. When I power up the computer with the 8-pin attached, I will see LED decroative lights on the MOBO momentarily flash then just hear a click from the PSU and no boot up.

One side note, when I was starting to remove things from the MOBO to check the PSU if it was getting over voltage or power draw, the first thing I removed was the wifi antenna. The GPU, all the RAM, and memory were still hooked up. I had the ATX 12V 8-pin connected and I did get fan start up, LED lights, GPU power for about 3 seconds then it all died. I never got that result again.

I am thinking something happened to my MOBO and just want to make sure before I buy another one.


Thank you!


Mar 15, 2018
It seems you actually dont know, that the CPU is running off the 12V supply line.
Sounds crazy, but it does, using voltage converters (those multiphase ones) to create its working core voltages.

Please dont mess around anymore removing/replacing power connectors.
Donno what you think you'd achieved with this first off anyway ?
It wont tell you anything meaningful.
The CPU LED will turn on if it doesnt have power to run.

There is a sticky on top of the hardware forum, which tells you how to bench a faulty PC.
The only tool you may need is a screwdriver and a bag of patience.
Oct 11, 2019
So I found that article and went through it all and still nothing. I cannot get the computer to boot up. Any other suggestions? I am leaning towards just getting another mobo.