Headset displays shut down randomly

Hey all!

I`ve been using my 8kx for over a year and it worked fine! Sometimes it was a bit finicky, but nothing I couldn’t solve.
Lately I have noticed that both displays might randomly shut off in 90hz mode. After going to 75hz they still turn off but come back after some time.
I checked all my display drivers and the display port driver and I can’t find anything.
Does anyone have an idea, where to look for a solution?

Thanks in advance!

Matthias

Hello Matthias,

This could be a bad cable.
Do you have an optical fiber cable or the default one?

I would suggest replug the headset again, make sure it’s plugged firmly at the both end.
Besides that, you may file a ticket with our tech support and providing the video/log files when encountering the issue.

Regards.

Thanks for the quick reply!
Tried reseating the cable but no luck.
I will write a ticket to support, just wanted to make sure I’m not missing something that is easy to fix!

Hello,

You’re most welcome.

If please let me know if you didn’t receive any response from our support!

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Anyone in the future - this is a cable issue.
Upscaling mode is good as a temporary workaround, but then you have to ship the cable back… which could take up to a year.

I wish it was so easy. After ordering the 6m cable and a normal 2 usb one I can say that there is no difference with my issues. The only thing I have noticed, is that the longer I play the more often there are flickers in upscale mode until it goes black for about 20 seconds. I’m waiting for support to respond to my latest batch of logfiles to tell me if there is a difference between the cables in the data.

Hi Matthias,
I’m trying to deal with a similar behaviour. As you wrote: using 8kx for almost a year, it worked fine, occasional finickiness, but solvable. Only difference is that I backed off from 90 Hz a while ago. I play sims, and for my needs 75 Hz is good enough, it allows for more eye candy.
Now for about three weeks I’ve been getting random intermittent shutoffs while in VR: After about 5–15 minutes, the screens turn off for a few seconds, then back on. Depending on which sim I am in, VR is resumed or must be manually restarted. Sometimes crash to desktop occurs. I am still trying to figure out which component is responsible. So far, I have ruled out these suspects:

  • GPU OC settings (I ran different combinations including stock, no change)
  • GPU driver version (tested three recent ones, no change)
  • HMD Cable (as was suggested above - seems fine upon inspection)
  • Performance hacks to increase FPS in MSFS 2020 (rolled back to former settings, no change)
  • PiTool version (after updating to latest version the HMD still randomly shuts off, but sometimes the sim keeps running, so I can restart VR. Previously the shutoffs resulted in crash to desktop).
  • SteamVR (shutoffs also occur when using MSFS with mbucchia’s PimaxXR, without SteamVR)
  • High system temps (CPU and GPU temps in HWinfo were okay before and during HMD shutoff, including GPU memory junction and hotspot.)
  • System instability (I don’t run CPU OC, and only mild GPU OC. Outside of VR, the PC has no issues. Passed RealBench stress test today.)
  • PSU (850 W, decent product)
  • Eye tracking module (I use it with a separate USB cable, not powered from HMD. Use it only for MSFS, unplug it for other sims.)

I strongly suspect that the fault is within the HMD. More specifically, I think it may be overheating, which either triggers the shutoff to prevent damage, or simply an electric component warps and disconnects. My issues coincide with high ambient temperatures from a hot summer. With the eye tracker installed, more heat gets generated and/or trapped in the device. I would really like to know if that is the case and what could be done about it, other than uninstalling the eye tracker (which worked fine before). I haven’t hat a satisfying VR experience in weeks. Cooler weather is approaching next week - if it gets better, I will report here.
@PimaxQuorra, have other 8kx users reported similar problems? Is there a maximum ambient temperature?

Regards, Arend

Seems fine upon inspection? What does this mean? Inspected how?

I don’t think you can determine if the cable is still good by just looking it over. I mean, if there’s obvious damage to the cable, then sure. But more typically when VR tether cables go out, they look perfectly fine.

The issue that you’re describing sounds very much like tether cable failure. The only way to really test this if just reseating the cable doesn’t work is to buy a new cable and see if that resolves the issue.

If you haven’t done this, I recommend that as your next step.

@Sargon, thanks for your suggestion. Here is what I did to check the cable: Reseated all plugs, PC side and HMD side, and on the PC side I tied the cable so movement in sockets was ruled out. I agree, that is just superficial and would not tell me whether anything is wrong inside the cable.
What is strange though: It ran fine yesterday for 10 or 15 minutes, then the shutoffs started occuring. Pushing on the plug to make sure it was not loose did not help. After leaving the HMD off for half an hour to “cool down” (my hypothesis), I could again run it for about 10 minutes before the next shutoffs happened. (Or can the cable itself overheat?!)
Anyhow, I will see if cooler weather improves anything, and will also consider replacing the cable.

The behaviors you’re describing are an exact match for what I’ve experienced with tether cable failures. Including where it will seem vaguely related to heat, weather, etc.

With my Valve Index, I experienced tether cable failures every 6 months like clockwork. With the Pimax 8KX, I experienced my first tether cable failure at 7 months.

And this is not just me. All of my friends have tether cables go out more or less regularly, too. The tether cable is a wear item. How long it lasts is dependent on how much you use VR and how vigorous your VR’ing is.

Note that this isn’t because the cables are badly made or anything. The cable to your monitor rarely moves and so will last basically forever. VR tether cables are constantly flexing during use, and they can only flex so many times before they fail.

So I was just unlucky ordering 2 new cables and getting some that are already damaged? Anyone else had that happen? Got the 4m cable and the 6m fiber optic cable and the result was the same.

I can still play in upscale mode for 10-15 minutes at time, then I get several short blackouts until the displays shut down for about 20 seconds and come back on. Sometimes it happens three times in a row, then it’s fine for a while.

Hello Arend,

Unfortunately, I haven’t receive any similar problems due with the headset temperature.

Mostly the issue can be sort out by replacing a new cable or debugged firmware.

But you’ve mentioned this incident only happened recently, it might related to the overheat.
Gonna forward to our engineers and ask them to inspect this.

Have a nice day.

Regards.

Thanks! I’ll keep you updated on my own findings.

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@PimaxQuorra – So the weather has been cooler for a week now, and my room has also returned to comfortable temperatures. The random shutoffs have gone away, even with the moderate performance tweaks I reintroduced. So whichever hardware component (PC, cable, or HMD) was failing due to overheating is not failing any more. :slight_smile:
I still suspect the HMD, because PC temps were okay during the shutoffs. Of course, most technical devices have a maximum operating temperature, so why wouldn’t a VR headset be limited to a certain level? I find that acceptable. Anyway I suggest that the Pimax engineers look into this, because it may be a simple explanation for 8kX failures that otherwise can’t be solved, and it would be nice to know the safe temp range beforehand. Also I could imagine newer products with higher performance could be even more sensitive to overheating. (AFAIK, Varjo Aero has active ventilation/cooling)

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Hi,

I have taken the time to do some last testing.

Tried it with both cables, different display ports and upscale and 90 hz.

Could someone tell me if there is a difference between the cables?

Here is the Google Drive Link:

https://drive.google.com/drive/folders/1YpIpSuKXMRydLrFrgp5XzMdpNnCoVaI2?usp=sharing

My opionion is that my diplay port on my graphics card is the culprit. My monitor has the same issue as the hmd, blackscreens and random flickers.

Anyone have any ideas how to test the graphic cards connection?

Thanks in advance!

I have no specific suggestion, but to further narrow it down you could try swapping the GPU in your setup. Maybe borrow one for that purpose, if possible with same specs.

Unfortunately I have no other graphics card to test it with.
It is getting worse though. Short blackscreens and intermittent shutdowns are getting more and more frequent.
Sometimes it works for 15 minutes without issues. At other times its impossible to play anything because it blacks out ever three seconds. When the screens turn back on, one of the screens is often frozen with the picture only displaying every second line or somesthing.

I really don`t know, what else to do.