Monitor keeps cutting in and out randomly

Let me clear one thing up right away: this isn't some weird quirk with my monitor. I’ve tested three different screens paired with three entirely different graphics cards, and the behavior remains identical across the board.

I was putting together a new rig for a buddy of mine, and once everything was finally assembled, I hit the power button. Everything sounds fine—fans spinning, lights coming on—but the screen stays completely black. It just sits there, cycling through input sources like it's searching for a signal that simply doesn't exist. No output whatsoever.

Then, after I kill the power and try again, it suddenly decides to work perfectly, booting straight into Windows 10 via a USB drive. I breeze through the installation in a few minutes and, ofc, get back to the standard Windows setup. But then, the cycle repeats: the screen goes dead again. The PC resets itself, fans are whirring, but the display is pitch black. If I shut everything down at the power strip and give it a little breathing room before turning it back on, it works again. Then it fails again. I managed to reach the desktop and start tweaking drivers, but as soon as I shut down and try to reboot, we’re back to square one. A little pause, an off-and-on sequence, and it works. It’s just this endless, frustrating loop.

Like I mentioned, I've swapped out multiple monitors and various GPUs with totally different port layouts, and the result is always the same. Every single combination of these components acts exactly like this.

The only thing crossing my mind right now is that the motherboard might just be a lemon. Should I just pack it up and send it back for a warranty claim?

I couldn't even test this using onboard graphics since I'm running a Ryzen 5 2600 x, which means there's no integrated graphics to fall back on.

The motherboard is an Asus tuf B450M-PLUS gaming.

I’ve also got my doubts about the motherboard, but if you can, maybe try swapping in a different power supply just to rule it out...

Larry Ortiz5 said:I’ve also got my doubts about the motherboard, but if you can, maybe try swapping in a different power supply just to rule it out...

We actually gave that a shot a little while ago, and honestly, it didn't change a thing. Still running into the exact same wall. I ended up dropping it off at the service center today to file a formal warranty claim, so now we just wait and see what they come up with.

So, I filed a warranty claim and this was the official response I got back: "Tested and working fine."
They ran it with a Ryzen 5 3600 paired with an R3 1200, using KVR26N19S8/8 RAM, a VS650 power supply, and an HD5450 graphics card. According to them, it boots, outputs video, and loads Windows perfectly enough.
Apparently, Windows PE works just fine, the internet connection is stable, and it passed an Aida64 stress test without breaking a sweat.
They’re running BIOS v1201.

Honestly, I’m at a bit of a loss here. What am I even supposed to do with that?

Give it a shot with a different power supply

Ryan Gonzalez4 said:So, I filed a warranty claim and this was the official response I got back: "Tested and working fine."
They ran it with a Ryzen 5 3600 paired with an R3 1200, using KVR26N19S8/8 RAM, a VS650 power supply, and an HD5450 graphics card. According to them, it boots, outputs video, and loads Windows perfectly enough.
Apparently, Windows PE works just fine, the internet connection is stable, and it passed an Aida64 stress test without breaking a sweat.
They’re running BIOS v1201.

Honestly, I’m at a bit of a loss here. What am I even supposed to do with that?

Wait, did you actually take the whole rig in, or just the motherboard?
If you didn't bring everything, it might be worth taking the whole setup down there. Might as well force them to deal with the actual components that are blocking the system from working properly.

Michelle Bennett5 said:Wait, did you actually take the whole rig in, or just the motherboard?
If you didn't bring everything, it might be worth taking the whole setup down there. Might as well force them to deal with the actual components that are blocking the system from working properly.

You can't just file a warranty claim for every single component; they only cover specific items. They won't take the whole machine unless you're looking to pay for the "service" of them inspecting the rest of it.🤔 🤦

Given how much they've been dropping the ball lately, we decided to just head over to Micro Center and pay them to assemble the whole build and run a full diagnostic on the system. They called us back in two days to tell us the motherboard was essentially toast—that was their exact way of putting it. Apparently, there are even deeper issues, and the thing won't even boot up unless it's running on a single stick of RAM because the board is so faulty.

And that’s the reality of what Protesilaus is claiming about the motherboard being perfectly fine... Honestly, my patience is starting to wear thin with this whole situation.