LG 31MU97-B True 4K Monitor Going Black then Display comes back every minute

[corinthos]

My 31" true 4K monitor by LG is going to black screen every minute or so and then comes back on in a second or two. I also see some flickering horizontal strips once in a while sometimes on the upper quarter or third of display, sometimes towards middle or bottom. flicking lasts only a split second or so.

Connection is displayport to displayport using cable from manufacturer. I purchased another one that is 15' long and the display won't even turn on with that one, so I reverted back to the manufacturer supplied cable.

After a little reading online, it appears others have this problem and someone resolved his by buying an ACCEL brand DisplayPort cable.

When I first bought my monitor, I don't recall encountering this issue. It seemed to take some time to start seeing and noticing it.

While the display goes black, the audio through the monitor also stops playing. If I change the audio device from monitor speakers to my bookshelf speakers, when the screen goes black, the audio still plays.

When I change from true 4K resolution to UHD to 1080P, I still see the flickering and screen going black before an image reappears.

I tried HDMI and it doesn't do this but the bandwidth is lower too right?

I don't know if the issue is with my monitor or video card (AMD Radeon RX480 8GB) DisplayPort and not sure how to further isolate the issue.

I ordered the ACCEL DisplayPort cable to try and should receive it early next week.

How can I troubleshoot this further?

I also tried 8bit instead of 10bit and still saw the same problem.

I looked at the end of the DisplayPort cable connected to the video card and didn't notice anything wrong.

Help?

 

[fleshconsumed]

Hard to say. I've also had trouble with RX480 and 4K monitors but over HDMI cable. Displayport worked fine for me. Try to find different videocard or different 4K monitor? That's the only way to nail down the problem.

 

[jackstar7]

In a situation like this, I would try to get the shortest cable possible that will reach between your video card and the monitor. Also, check around for anyone having DP cable issues. They definitely exist and several brands are thought to be safe. I believe my best experience was with Cable Matters. YMMV and good luck.

 

[chubbyfatazn]

So I have this monitor and ran into a lot of these issues as well...

My 31" true 4K monitor by LG is going to black screen every minute or so and then comes back on in a second or two. I also see some flickering horizontal strips once in a while sometimes on the upper quarter or third of display, sometimes towards middle or bottom. flicking lasts only a split second or so.

My first guess would be the cable

Connection is displayport to displayport using cable from manufacturer. I purchased another one that is 15' long and the display won't even turn on with that one, so I reverted back to the manufacturer supplied cable.

Stick to <= 10', the shorter the better

After a little reading online, it appears others have this problem and someone resolved his by buying an ACCEL brand DisplayPort cable.

I'd read this as well and ordered the same cable. It didn't work for me. What did work though was a standard 6' Cable Matters cable (which is incidentally one of the ones the interwebz said would NOT work).

When I first bought my monitor, I don't recall encountering this issue. It seemed to take some time to start seeing and noticing it.

Neither did I. And then my monitor's EDID got corrupt, and since I don't have the proper tools to do a reflash I just used a software hack to get it to UHD 4k and called it a day

While the display goes black, the audio through the monitor also stops playing. If I change the audio device from monitor speakers to my bookshelf speakers, when the screen goes black, the audio still plays.

When I change from true 4K resolution to UHD to 1080P, I still see the flickering and screen going black before an image reappears.

No clue about audio, sorry. Never used it

I tried HDMI and it doesn't do this but the bandwidth is lower too right?

Correct - it's only an HDMI 1.4 port. Which only goes up to 1920x1080 @ 60Hz. I think I have an active HDMI 2.0 adapter lying around here somewhere if you want me to see if that works, though

I don't know if the issue is with my monitor or video card (AMD Radeon RX480 8GB) DisplayPort and not sure how to further isolate the issue.

I ordered the ACCEL DisplayPort cable to try and should receive it early next week.

How can I troubleshoot this further?

I also tried 8bit instead of 10bit and still saw the same problem.

I looked at the end of the DisplayPort cable connected to the video card and didn't notice anything wrong.

Help?

Doubt it would be the GPU, definitely not the 8-bit/10-bit setting. Got another monitor with DP/mDP to test?

When you go below true 4k, is the picture consistent and clear (using the mfg cable)? Or does it flicker as well?

 

[alcoholbob]

My 31" true 4K monitor by LG is going to black screen every minute or so and then comes back on in a second or two. I also see some flickering horizontal strips once in a while sometimes on the upper quarter or third of display, sometimes towards middle or bottom. flicking lasts only a split second or so.

Connection is displayport to displayport using cable from manufacturer. I purchased another one that is 15' long and the display won't even turn on with that one, so I reverted back to the manufacturer supplied cable.

After a little reading online, it appears others have this problem and someone resolved his by buying an ACCEL brand DisplayPort cable.

When I first bought my monitor, I don't recall encountering this issue. It seemed to take some time to start seeing and noticing it.

While the display goes black, the audio through the monitor also stops playing. If I change the audio device from monitor speakers to my bookshelf speakers, when the screen goes black, the audio still plays.

When I change from true 4K resolution to UHD to 1080P, I still see the flickering and screen going black before an image reappears.

I tried HDMI and it doesn't do this but the bandwidth is lower too right?

I don't know if the issue is with my monitor or video card (AMD Radeon RX480 8GB) DisplayPort and not sure how to further isolate the issue.

I ordered the ACCEL DisplayPort cable to try and should receive it early next week.

How can I troubleshoot this further?

I also tried 8bit instead of 10bit and still saw the same problem.

I looked at the end of the DisplayPort cable connected to the video card and didn't notice anything wrong.

Help?

With displayport what matters is length of the cable and gauge, and to a lesser extent, the signal sensitivity of the display controller (although you can't control this last aspect much once you've decided on a monitor...).

I happen to have the LG as well as a Crossover 434K UHD monitor.

Since your monitor is 4096x2160 instead of 3840x2160 it needs a bit more cable thickness than normal. For example, I can run a 25 foot, 26 awg DP cable to the Crossover 434K with no issues.

Whereas that same cable flickers with the LG 31". I have to drop down to 16.5 foot, 24awg DP cable with the LG to get a stable image without flickering.

 

[corinthos]

It wound up being the included DP cable.. something happened to it, maybe, when I swapped systems and moved things around. I may have put too much pressure on the connector end that plugs into the video card when I tried to fit the chassis inside of a small space with limited room in the rear, requiring me to apply some pressure on the cable by channeling the cable at a near 90 degree angle due to limited room in the back. That's my guess, anyway.

Bought a new cable confirmed to do true 4K and the flashing black screen issue is gone. I doubt my bending the cable caused the issue because the issue was present even before I swapped systems and moved it.

Wondering if cables just go bad over time somehow... Pretty sure it's the cable that came in box, but will have to double check. It is a pretty thick cable and was a decent length for an included cable.