Question Constant distorted green screen, even when unplugged

[zajdyi]

Hi,
my monitor, Iiyama G-Master GB3266QSU, suddenly got a strong green distortion. I realize that it's probably a faulty monitor, but it's only 5 years old.

This has happened first several months ago, and I think I fixed it by unplugging and plugging it back in. But that time, it happened while a game was changing my resolution and it hasn't happened again until now. So I didn't think much of it.

Now, it happened randomly (watching a YouTube video), and it doesn't go away.

Symptoms
The screen has heavy green tint and vertical lines are visible.
I can't see what is happening on the screen, but Windows seems to boot normally.
I can see the screen react when I move my mouse (a brighter line moves across the screen).
I can't get into the monitor settings, because they're also distorted.
Bios, same.
With PC turned off, the "No signal" is distorted as well.
Unsure if related, but a few days ago my monitor started displaying everything at 1 frame per second. Turning the monitor on off solved it and it hasn't repeated.

Images

https://imgur.com/a/hdKytRY

Things I've tried
Restarting PC.
Turning monitor on off.
Leaving it off for 30 minutes.
Plugging cable in out.
Switching to a different port on both monitor and graphics card.
Switching to HDMI cable.
I don't have another PC to try.

Since switching to a different cable hasn't helped, I assume it's the monitor or GPU.
Mostly I want to make sure that it can't somehow still be the GPU, even though it persists even when it's unplugged.

I appreciate any help. Thanks.

 

[Lutfij]

Welcome to the forums, newcomer!

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

I don't have another PC to try.
If the display behaves the same on a donor PC/platform/laptop as it has on your system, then the monitor has conked out. Just an FYI, if the monitor isn't hooked up to anything, except power, and you're yet seeing the green screen, then the display needs replacing.

Likewise, you source(borrow, not buy) another monitor to hook up to your system to see if your issue persists, that way you rule out your GPU being the root of the problem.

 

[zajdyi]

The monitor is actually working again, but now I'm even more confused.

I tried plugging it into different ports again. This time while I was in Bios, not sure if it's relevant. Suddenly it started displaying normally after I plugged it in. I didn't do anything different than what I've already tried multiple times before. And actually it's in the same port now as it was to begin with.

The display was indeed not working even when unplugged. "No signal" message displayed distorted after a while as shown in one of the images.

That's why I really don't understand how it's working now. It turns on and off normally.

I would think it's a cable or a port issue, but there was no change when using HDMI.
If it's a monitor issue then why would plugging it in and out multiple times change anything? Especially when it wasn't working even unplugged.
And if it's a GPU issue then why would it be green even when unplugged?
I have no idea how this works, but could it actually be a software issue? With the monitor's firmware maybe?

I assume it will happen again. What should I do to find the cause, now that I can actually see the screen? Trying a different monitor or PC won't tell me anything, since it's working currently.

I'm not sure about all the specs, but here is something.
CPU: i7 13700KF
GPU: RTX 4080
OS: Windows 11
Monitor: Iiyama G-Master GB3266QSU

The PC is 2 years old, except the monitor, which is older.