Gigabyte M32U Screen goes black when plugging in appliances or even just cords

[optionen100]

Hello everyone.
I have a Gigabyte M32U 4K Monitor. I quite like this monitor so i do not want to  exchange it for another model.
They are known for randomly showing a black screen for 2-3 seconds. (HDMI Compatibility/RGB/Sync related issues), but this isnt the case for me.

My problem is:
Whenever i plug in something in any socket in my room, the screen goes black for 2 seconds. It can be anything, from phone charger to an EMPTY powerstrip.
 Even plugging in a UNPLUGGED PC power cable will mess with the monitor, every time, without fail. I can Plug and Unplug it straight for a minute and the monitor will stay black..
This can also happen when something else is turned on in another room, which can be really annoying while gaming.
I have 4 Monitors, only the M32U goes black. Swapped cables and ports, no difference.
I am honestly completely out of ideas.

Checked:
- Mains Voltage Stable at 231V , drops to 230V when playing a game.
- Ground to neutral, 0V and 0.2V when i apply a heavy load ( used an cheap "smart" mains polarity tester to confirm polarity and voltage drop)
- Tested with new ground to breaker box, same results.

I would appreciate any idea you might have.
I hope this is the right place to ask, also sorry for my writing skills, i am trying 

[coromonadalix]

it seems you have spikes ... have you tried   emi rfi  ac line filters ??

[tom66]

Get a new HDMI/DP cable with better shielding.  This is a common problem with cheap HDMI/DP cables.  It happens with my monitors but infrequently until I rerouted the data cable to avoid the power cables.   The problem is some monitors are more sensitive than others and they can take some time to recover from loss of sync.

If you can adjust the HDMI drive strength on your graphics card that may also mitigate the issue but fundamentally the problem is transients getting onto the data pairs upsetting the monitor.  4K144 data rate (for your monitor) is "absurdly" high and it does not take much to upset it.

[optionen100]

Get a new HDMI/DP cable with better shielding........

I already tested 4 different DP Cables, from factory to overpriced (but really good) 30€ cable.
Also tried without Vsync/GSync/Freesync, @60HZ and HDR disabled. No difference.
I completely forgot to say that this also happens without a video signal at all. It seems like the monitor itself is upset about something.

it seems you have spikes ... have you tried   emi rfi  ac line filters ??

Yes i recently added a Powerstrip which has some filters build in. Its a German brand which had been tested sometimes, they are trustworthy.
PC and monitor share the same powerstrip. But also happens when connected to different outlets.

Here is a video showing the problem. Forgive me for the messy floor.
https://youtube.com/shorts/n1LaNWptLTU

[optionen100]

Okay it seems like a found the (or a) problem.
My monitor also has a USB port for uploading settings and firmware. I plugged it into my PC and now the issue is gone.
Its either some sort of firmware problem, or more likely a internal grounding problem.
The monitor uses a European 3 pin plug. So its grounded. Maybe it isnt connected internally and now it uses the USB cable as a ground? But then, the DP cable is also shielded, so it also could provide a ground.
Have to take it apart when i get the time.

[wraper]

Okay it seems like a found the (or a) problem.
My monitor also has a USB port for uploading settings and firmware. I plugged it into my PC and now the issue is gone.

Yet another proof you have a crappy video cable. Way way less likely it's improper ground connection on HDMI/DP connector inside the monitor. But as you say black screen is a common problem with this model, I would not totally exclude engineers doing GND shenanigans to prevent elusive "ground loops."

Also tried without Vsync/GSync/Freesync, @60HZ and HDR disabled. No difference.

But you did not lower resolution which actually would way more likely make the difference. Also 4k at 144Hz needs a good short cable. Expensive does not mean good though.

[optionen100]

But you did not lower resolution which actually would way more likely make the difference. Also 4k at 144Hz needs a good short cable. Expensive does not mean good though.

I just tried setting it to 1080p and lower resolutions. Same behavior. This is my 4th DP cable, its unlikely that they all have the same fault.
Current cable is VESA certified to "DP1.4 8K @165HZ HDR10" 1 Meter length
https://kabeldirekt-store.de/en/products/8k-vesa-displayport-kabel-1-4

I could get a DP2.0 Cable but my GPU and monitor both use DP1.4.

[wraper]

Just in case measure resistance between connector shells on both ends. They must be connected together but it's not always the case in crappy cables. Also is it the same when connected to different GPU output?

I could get a DP2.0 Cable but my GPU and monitor both use DP1.4.

There is no reason to particularly buy cable with older spec version. There are no backwards compatibility problems. Also I would avoid cables with gold-ish color connectors. Usually it's a sign of Chinese garbage with no gold plating whatsoever on the shell and barely any if at all on the pins. Prefer normal nickel plated ones.

I just tried setting it to 1080p and lower resolutions.

Then I guess it's either monitor and GPU issue. However in my experience it was always bad cables even when I thought it was a bad monitor or GPU when multiple Displayport cables supplied with over EUR 1000 Dell monitors have gone bad after a few years with issues similar to yours.

[optionen100]

Thanks for your help!

Just checked resistance between both ends.  0.9 Ohms . The cable supplied by the manufaturer is actually lower than this. Its 0.4 Ohms. Same result but i cant even select 144HZ with it.

Then I guess it's either monitor and GPU issue. However in my experience it was always bad cables even when I thought it was a bad monitor or GPU when multiple Displayport cables supplied with over EUR 1000 Dell monitors have gone bad after a few years with issues similar to yours.

I already had this issue on my GTX 1080. Now im on a RTX3080. Already tried switching ports and cables with the monitor next to it (Samsung).


I think i will just do a bunch of research and buy a known good brand just to be sure
I hate how hard it actually is to buy some "good" things in Germany. The market is flooded with cheap Made in China stuff, every supermarket has its own little knock of brands. Dont know what to trust

[wraper]

Thanks for your help!

Just checked resistance between both ends.  0.9 Ohms . The cable supplied by the manufaturer is actually lower than this. Its 0.4 Ohms. Same result but i cant even select 144HZ with it.

Then I guess it's either monitor and GPU issue. However in my experience it was always bad cables even when I thought it was a bad monitor or GPU when multiple Displayport cables supplied with over EUR 1000 Dell monitors have gone bad after a few years with issues similar to yours.

I already had this issue on my GTX 1080. Now im on a RTX3080. Already tried switching ports and cables with the monitor next to it (Samsung).


I think i will just do a bunch of research and buy a known good brand just to be sure
I hate how hard it actually is to buy some "good" things in Germany. The market is flooded with cheap Made in China stuff, every supermarket has its own little knock of brands. Dont know what to trust

The safest bet would be something like Amazon Basics. Good cable does not need to be expensive. There is very little correlation between quality and price, and a lot of overpriced garbage not adhering to standards.

[optionen100]

So i just tested 2 new DP Cables.
- First one is a Amazon Basic one. 1.4 Spec. Same behaviour even at 1080P.
- Second one is a KabelDirect (same brand as previous cable) Spec 2.0 WORKING

Thats really strange. Maybe this monitor is just really sensitive. There isnt even a device that needs spec 2.0 on the market yet.

I will update if the random black screen issue (that a lot of people with this monitor have) is also gone.

Thanks @wraper