Display signal randomly drops in KVM or monitor

I have a L1 DisplayPort 1.4 4 Port KVM connected to an ASUS Tuf VG28UQL1A and the monitor will randomly lose the display signal (it goes black and says “No Signal”). This happens with all of the computers connected to the KVM, and
all of them will also no longer detect the monitor. Everything usually works again when I power cycle the monitor.

I’ve noticed that it happens more often when I am playing games at a high framerate. Usually when it happens in a game, there’s also an accompanying brief clicking/popping sound. But because this happens randomly and quickly, I haven’t been able to identify what is producing that noise.

Does anyone have any suggestions for how I can identify the issue and fix it?

Is there any way you could get a video to help us troubleshoot your issue?

I’ll try to get a video, but it doesn’t happen all that frequently.

I managed to get a video of it happening but I am not sure how to upload it. My account is too new to upload files so I uploaded it to youtube, but apparently I am not allowed to post links so that doesn’t really work either.

You can hear the clicking/popping sound as it goes black, and then the monitor has no signal, and turns itself off. It takes a few seconds for it to register that I hit the power button to turn it back on, and then it’s fine.

For some context on the frequency of this happening, this was the first time this issue happened since I made this thread. But I’ve also have had it happen 3 times within 2 hours several weeks ago. This frequency of once every couple of days is more typical. The monitor did also lose signal yesterday (when I wasn’t filming), however there was no sound so I am unsure whether that is the same problem.

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I suspect the signal is “borderline” or one of your cables is picking up outside interference from something.

You could try adding some ferrite clips which help squelch outside interference:

or pickup some Club3d DP cables which are higher quality and that will more likely clear things up for you.

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@wendell Thanks for the suggestion. I’ve purchased some Club3d cables. Hopefully this will resolve the issue.

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sounds good. I just had two different people, one in germany, that seemed to get fake cables. Fibbr brand fiber optic is also another good choice in case you have trouble but lmk.


How can I tell if the cables are fake?

At first, the Club3d cables were noticeably worse. The signal would drop every couple of minutes. During that time, I was able to figure out that the popping noise was coming from my monitor’s speakers, so I guess that’s caused by interference on the audio lines?

However the cable I hadn’t replaced was the right angle adapter since I have a Meshlicious case. After I removed that and plugged the cable in directly, the signal hasn’t dropped since, although it’s only been a few hours. I’ll need to get a higher quality right angle adapter as having the computer on its side is not a viable long term solution.

Oh yeah if you don’t have club3d on both sides then that could cause issues. It’s weird it’s worse though? Could be an impedence mismatch I guess.

There’s about 4 training levels a monitor can do tomorrow to negotiate with the GPU that happens at a pretty low level. If you were training at max, level 4, and with club3d level3 is too little but level4 is too much then you can be in a weird no man’s land of snr ratio. Sometimes a ferrite bead cleas that up

So maybe try a ferrite bead on your right angle cable?

Sorry for the delay on trying this, was away from home.

I tried putting a ferrite bead on the right angle adapter. It helped a bit but the signal still dropped out frequently. I’ve also tried a different right angle adapter which has the same issue but less often. I have Club3d cables on both sides of the KVM.

Have you tried without the right angle adapter?

Yes, it doesn’t seem to have issues without the adapter. However my case is a meshlicious which requires having it putting on one side in order to do that, so I’m not sure if that’s good to do long term.

I’m also trying the new adapter with ferrite bead with my original cables since the signal wasn’t dropping that often with them.


There is a bit of black magic to the ferrite beads, for sure. You might need two. Try two on the right angle adapter, about 1.5cm away from each end of the cable?

I can mail you some 3d printed feet to give the meshlicious a little more lift if that would help haha :slight_smile:

The adapter is actually not long enough to have two beads, more than half of it is inside of the case. I’ll just keep with the current setup of adapter + bead + original cables and see if the signal still drops. So far it hasn’t, but these cables would only have that issue every few days so it might be a while.

I actually have a 3D printer so I can print my own feet. I have some feet but they’re too short to fit straight DP cables and I haven’t gotten around to remodeling them to be taller.

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@wendell mentioned some folks getting dud Club3d cables recently - add me to that list. I RMA’d my KVM under the assumption that my cables were fine and that there was some issue with the KVM, but I managed to fix my issue by getting different cables.

Specifically, my setup was:

PC/RTX 3080 → Club3d CAC-2067 1m DP to DP → KVM PC1 (either port) → Club3d Club3d CAC-2068 2m DP to DP → Gigabyte M32U

I had issues with the monitor losing signal and restarting over and over when I did anything above 4k60Hz with greater than 8-bpc.

I also swapped my MacBook Pro from work into the PC1 ports, with that setup being:

MacBook Pro → Club3d CAC-1557 2m USB-C to DP → KVM PC1 (either port) → Club3d CAC-2068 2m DP to DP → Gigabyte M32U

… which also failed badly.

So, I swapped the cable from the KVM to the monitor with a Club3d CAC-2067 1m DP to DP, which also failed.

I’ve switched over to using FIBBR cables, and they seem better so far. I had a bit of weirdness off the bat with them, but I think they’re more stable, at least. I experienced 1 flash of my screen, which I’m really hopeful was just a fluke getting everything connected, at 4k144 10-bpc.

What length FIBBR cables are you using?

I’m running 2 of the 2m FIBBR cables now, one from GPU to KVM, then from KVM to monitor. With their (expensive) fiberoptic cables, length is theoretically less important by my understanding.

Thanks @wthefourth I have two 2m cables on the way as I heard the 1m cables aren’t the best

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Slight update on my setup now - everything has been smooth sailing for several days, and it’s really been great. Shout-out to FIBBR cables.

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I’d like to chime in with dud Club3D cables. They looked legit to me, came in a Club3D branded bag, with Club3D branded plugs and a Club3D tag with part number (CAC-2068) and I tried 2 of the 6’ variety between my PC and the KVM and experienced constant drops and resyncs, however my much thinner braided 10’ monoprice cable works fine and has not exhibited any drops or resyncs at 4k144. An identical 6’ monoprice cable I just purchased is being far less reliable however, I might have to go the FIBBR route… I’d be happy to offer up one of these new 6’ Club3D cables to L1T as a sacrifice for testing, hell you can have both, they’re both pretty useless for my use case, I think I have an extra 3 footer too, I’m curious as to the current quality of those as well…

Also I tried a Club3D 2 port MST hub as the 3 port version doesn’t seem to be in stock anywhere and the 2 port one claimed it could split to 2x 4k/60, but I could only get one at 60 and the other at 30. I’m using a SIIG MST hub now and it does do 4k/60 on both now, but with both I occasionally see flickers of white squares in one or both monitors. Not full drops/syncs, just for what seems like a single frame there will be a white square that takes up a good portion of the screen in one corner. This was more severe on the Club3D hub but still happens on the SIIG. Definitely happens more on cables that give my main display more issues.

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