Question Mobo faulty? PC turns on, but Screen and any USB peripherals stay dark. Sometimes works for days or months, but then suddenly the issue is there again

[statistx]

I am at my wits end, so I want to ask here, if anyone has an idea before I replace my motherboard, since by process of elimination that seems to be the most likely culprit.
Specs are at the end of the post.

Issue:
Sometimes (weeks or even months between the issue) when I turn on the PC the Screen (which is connected by HDMI) and all USB devicses are not starting up with it, means they stay black.
I once had luck by hitting Reset and it came back up, but the other times I always needed to do the following: Unplug power, unplug every device, WAIT (cause just plugging back in and trying again never worked right away) and then after a while I plug everything back in and try again and it might work.
When it works, the PC runs perfectly for hours (and days, cause I had that issue before 3 free days before and decided to not risk it and keep it running).
When I turn it off, the next time is a 50/50 gamble. Could work for days, or not.
The PC itself SEEMS to start up to windows, just in terms of HDD sound and how it sounds generally, but I can't confirm it, since I don't have a screen.

What's old and new in the PC:
I replaced my Tower and PSU recently (The PSU one day decided to kick it, turned the PC on and it did not start at all, so had to replace it and it worked afterwards (aside from the discussed issue)), so they are new.
Issue existed before and after replacing those.

GPU, Secondary HDDs (for storage), USB devices are all from my old PC and work on the old PC, so I doubt that's the issue. SDD with OS was replaced, but the Issue existed before and after that.

I got the MOBO, CPU and RAM at the same time second hand. Any of the other hardware in this PC is NOT from that build. Which leads me to believe the issue lies here somewhere.

I doubt it has to do anything with Windows, since the issue begins before the PC even has to get to windows, since I would see the Bios bootup first.

What I tried:
I replugged everything (power cables inside the PC, different Sata ports for the HDDs, RAM), chose new USB ports for the peripherals and updated UEFI to the latest version.

Specs:
OS: Windows 10 Pro 64bit
CPU: AMD Ryzen 5 2600
Motherboard: ASRock B450 Pro4 (AM4)
RAM: 16GB (2x8)
GPU: Nvidia Geforce GTX 1060 6GB
Storage: 1 SSD: Samsung SSD870 EVO 500GB, 2 HDD: Toshiba HDWD130, Seagate ST2000DM008

Closing words: I can only assume the Mobo has some issue, so I plan to replace that, but maybe someone here has different knowledge or ideas, cause I would prefer not to do that.

 

[Ralston18]

Check Reliability Monitor and Event Viewer.

Any errors, warnings, or even informational events being captured just before or at the time the screen and USB devices go dark?

Are you able to swap in another known working HDMI cable?

Does the problem occur if you boot into safe mode?

 

[statistx]

My Motherboard does not have a beeper or what it's called, so I get nothing. Just from the way the PC sounds when it happens, it seems it just boots normally up to windows, but without a screen I can't tell. Thus I also don't see any possible error messages.
HDMI cable is not the issue (switched it out at some point, cause at the very beginning i thought it was related to the screen) and also any USB peripherals also don't power on.
Can't boot into safe mode for the same reason: Don't have a screen or keyboard.

Basically it seems that the PC turns on, but everything connected to it doesn't know and stays dark.

I did not know about Reliability Monitor, so now I looked at it.
It only says "Windows did not shut down properly" which I'd say means it DOES definitely boot up to windows. The shutdown was me hitting the power button, cause I didn't have screen and so on. So other than that, nothing shows up.
Also looked at Event Viewer, but I honestly have no idea what to look at there, but considering the Reliability Monitor result, I'd say the issue does not seem OS or software related.

(I'll note it for accuracy, but does not seem related, the only other failure i see in reliability monitor is a 0x800706D9: 9WZDNCRFHVJL-MICROSOFT.OFFICE.ONENOTE update error, which should be fixed by turning on printspool service according to google, but checking the dates that error comes up, it does not relate to the times the PC has my issue)

 

[Ralston18]

Current PSU: make, model, wattage, age (recently being?), condition: truly new, or perhaps refurbished, used?

Did you reuse any cables from the original(1st) PSU for the new (2nd) PSU?

Event Viewer is not at all as user friendly as Reliability History. However, you can explore and will probably learn your way around fairly quickly. You can click any given error(s) for more information and detail. That information and detail may or may not be helpful. (Applies to Reliability Monitor as well.)

All in all I suspect a loose connection/faulty plug based on the problem being intermittent. And the loss of power may have, in turn, caused file corruption which makes things worse.

Power down, unplug, open the case.

Clean out dust and debris.

Verify by sight and feel that all cards, connectors, RAM, jumpers, are fully and firmly in place. Noted that you have done that to some extent. Add using q a bright flashlight to closely inspect all plugs and ports for signs of damage and (for ports) any sort of obstructions.

Likewise inspect all components for signs of damage: bare conductor showing, melted insulation, browning or blackening, swollen components, kinked or pinched wires, Remember to check the case (tower) and around the I/O port. Inside and out.

While you are doing that, swap in a new CMOS battery. Just as a matter of elimination.

This motherboard (verify):

https://download.asrock.com/Manual/B450 Pro4.pdf

Use the manual (or the applicable manual if my link is not correct) to double check all connections and configuration settings.

Take your time, read carefully. Check manufacturer's FAQs and Forums for more information as necessary.

It could indeed, narrow down to a mobo issue. Hopefully not, but in any case once there is some certainty about that being true then you may be able to RMA the board or at least be comfortable that a replacement motherboard will resolve the problem.

 

[statistx]

PSU is 2 months old at best and it's a Gigabyte P750GM 750W ATX. Cables are all new, since the old one was with fixed cables and the new is a modular one. Wasn't refurbished either, just storebought.
Since I replaced the whole case, I also rebuilt everything in there (well except of course CPU on motherboard) so it also was cleaned out. I did not see any damages, last time I checked, but I am more in the realm of software than hardware, so if it isn't anything very noticable i might miss it.

I was wondering about the CMOS battery. Not sure how that would work, but considering it needs unplugging from power AND waiting, I'm not sure how fast that thing does anything on it's own.
Regarding the motherboard and everything being connected: I spent several hours with the manual and a discord chat with a friend, so I am pretty sure everything is where it's supposed to be. Last time I unplugged and opened up (so about 2 weeks ago I'd say) when the error occured before, I also went over where everything is and i still did not see anything out of place, so gonna assume I got everything where it belongs.

Gonna check to replace the CMOS battery.
Honestly I'd prefer it being a mobo issue rather than a CPU issue, just because of the cost. I am not looking forward to being forced to learn how to switch out a CPU (so I can use the old one on a new mobo), but still better than having to buy a new CPU.
Only plus side is that the Mobo won't cost me any of my non-existing budget, cause I got a giftcard from my workplace which sells motherboards, so I can get one for like 20 bucks basically.

"Funny" thing is, I've seen a few posts about the same issue here and there, but never a solution and even 2 friends who are pretty savy with PCs and several coworkers who constantly upgrade their systems had no idea or clue anymore.

 

[Ralston18]

Fair enough.

Do take the time to carefully read the applicable motherboard user manual for any given motherboard(s) and Revisions that you have in mind.

Ensure that the motherboard fully supports the components (CPU, RAM, etc.) that you now have and intend to reuse or otherwise will be purchasing. Check the QVL (Qualified Vendor's List) on the motherboard's manufacturer's website. Confirm as much as possible.

Play close attention to all fine print, caveats, etc..

Read site FAQ's and Forums as well. Pay attention to both what is said and what is not said.

Details matter.

 

[statistx]

Fair enough.

Do take the time to carefully read the applicable motherboard user manual for any given motherboard(s) and Revisions that you have in mind.

Ensure that the motherboard fully supports the components (CPU, RAM, etc.) that you now have and intend to reuse or otherwise will be purchasing. Check the QVL (Qualified Vendor's List) on the motherboard's manufacturer's website. Confirm as much as possible.

Play close attention to all fine print, caveats, etc..

Read site FAQ's and Forums as well. Pay attention to both what is said and what is not said.

Details matter.

I went a bit further than intended and got a Mobo (msi 570x gaming plus) with a giftcard from my work, but since it felt wrong to take apart a sometimes working CPU/MB combo and install an old CPU on a new Mobo, I also bought a CPU now (Ryzen 5 5600X), so now I can casually install that on the new MB and replace it in the case whenever and don't need to rush to do everything on the same day or be without a PC til it's finished.