red cpu light issue, psu restart fixes it

[mistmistmist]

So, earlier this week I had my very experienced friend build me a new pc for school/gaming off some parts we found on quite good blackfriday prices. 

 

First boot went well, and we updated the bios without issue. After that we turned the pc off and when we tried to boot it again into bios, it started up, but had a red cpu light on the motherboard and no display. We tried restarting with the power button, but it didn't work. What eventually fixed it, was restarting the psu by reconnecting the power cable and flipping the switch off and on. Then we installed windows without issue and installed drivers and software.

 

After that, every time I turn off the pc and try to boot it again, it shows a red cpu light and I get no display. Restarting works without issues though. Restarting the psu by reconnecting the power cable seems to be the only thing that fixes it and lets me boot up the pc normally. However, it would be nice to know what's causing it and if there's anything I can do to make it boot normally on the first try.

 

All the parts are new, and I am fairly confident that none of them are faulty or poorly installed/connected. Today, suspecting a memory training issue, I tried letting the pc boot on its own when it showed the red cpu light, but it went on for over 3 hours without anything so I just turned it off with the power button.

 

in bios, i have fast boot disabled and expo profile set to the cl30 6000mhz. 

I also have cpu 105w mode on, pbo on and tjmax set to 85c.

 

Here are the specs,

motherboard- asrock x870 steel legend 

cpu- ryzen 7 9700x

cooler- noctua nh-d15s 

ram- g.skill trident z5 neo cl30 6000mhz 2x 16gb

ssd- wd_black sn850x 1tb

gpu- rtx 4060 dual oc

case- fractal design torrent white tg clear

psu- seasonic focus gx-750 atx 3 (2024)

[AAVVIronAlex]

Could be the PSU.