EEVblog #1107 - Shocking 4K BENQ Monitor Problem!

[wraper]

What's worse is if you turn off a monitor, it causes Windows to go haywire and shuffle all our applications all over the place.

That's certainly displayport connection, HDMI interface does not care if monitor is ON/OFF. Did you try to change the cable? There are a hell of a lot DP cables in the wild which don't follow the standard. Including backfeeding power from monitor to GPU.

[BrianHG]

HDMI interface does not care if monitor is ON/OFF. Did you try to change the cable? There are a hell of a lot DP cables in the wild which don't follow the standard. Including backfeeding power from monitor to GPU.

Yes HDMI does.  It's a feature of some monitors and video projectors to hold the monitor ID and state even when the power is cut off.  In my video scaler, I had specific circuitry on my HDMI and DVI inputs to retain this feature.

Example, my BenQ TH670 , when powered down, my laptop doesn't care and thinks it's still connected and at 1080p, even if I remove the projector's 120v power chord.  As long as I don't remove the HDMI cable, it retains the video mode and setup.  With my stupid newer BenQ and Optoma HD142X, just turning off it's power on the remote control F--KS everything up.  (Why is everything getting so cheap and short sighted today... The manufacturers claim it is a feature when the engineering knows you save around 50 to 90 cents by not having the feature...  Even my 4 year old BenQs didn't mess up windows when I turned them off...) Thankfully, I can plug my laptop into my video scaler, then into these garbage newer cheaper crappy junk to fix that problem.  There also exists external DVI/HDMI EDID clone/bypass boxes which offer the same feature.  They also might exist for display port as well.

[EEVblog]

Cable changed to what looks like a really good quality one, now it's just turning off without me moving. Maybe David moving behind the monitor, I don't really know.

[wraper]

Cable changed to what looks like a really good quality one, now it's just turning off without me moving. Maybe David moving behind the monitor, I don't really know.

Is it HDMI or DP? I've seen like a dozen of Raspberry Pi with one half of HDMI differential transmitter been blown almost short to GND but monitor still displaying image most of the time. Although in such case it likely won't work at all @ 4k.

[Brumby]

Maybe our HDMI cables need a tinfoil hat...

I have a couple of soldering stations and power supplies in a small wooden shelf unit I made which sits about 2" to the right of my rightmost monitor.  One of the soldering stations has the main power switch at the back which means it is always switched on - but I have the whole group of devices on a master power switch.

Sometimes when I switch on this master switch nothing happens to the neighbouring monitor.  Sometimes I get a fleeting black line and sometimes the whole screen goes black for a couple of seconds.  My left monitor has never skipped a beat.

[BrianHG]

Cable changed to what looks like a really good quality one, now it's just turning off without me moving. Maybe David moving behind the monitor, I don't really know.

@Dave, first try a lower res video mode if allowed, then try a different PC or video card.  Something sound just too flaky.  Note that inside some monitors, the video input connector is on a daughter board, then with a cheap ribbon cable, or even cheap single stranded wires, the video is fed to the monitor's main PCB.  This is a weak point where a flaky wiring or bend in the wiring in the case of the stranded wiring type sometimes leads to a semi-lemon monitor video input.  Try using the monitor's alternate video input.  If this makes no difference, then it is most likely not a problem with the monitor itself.  Also make sure your HDMI cable is truly 4K PC RGB 4:4:4 compliant and not one of those crummy lower bandwidth cables which work at 4K in home theater setups where the run the color in a lower bandwidth 4:2:2 mode.  I've gotten this type of shaft before, those HDMI cable just don't work at all on a PC.

[Red Squirrel]

What's worse is if you turn off a monitor, it causes Windows to go haywire and shuffle all our applications all over the place.

That's certainly displayport connection, HDMI interface does not care if monitor is ON/OFF. Did you try to change the cable? There are a hell of a lot DP cables in the wild which don't follow the standard. Including backfeeding power from monitor to GPU.

Interesting, yes I believe they are mostly DP.  Is there a way to disable this "feature" without a new cable?  Or is there something to look for if buying a new cable?  I don't imagine this is something specific they would advertise so don't want to keep buying cables just to try.   

Also this flicker issue for us at work persists even with different cable.  Pretty much everything has changed at some point or the other including the monitors themselves. It's really weird.   The ferrite rings seem to have helped in Dave's video though... it may not have fixed it completely but seems it was not happening as much.  I may get some and give them a shot at work.

[wraper]

Is there a way to disable this "feature" without a new cable?  Or is there something to look for if buying a new cable?

Nope, you won't be able to disable it even by changing DP cable. You certainly should avoid cheap ebay cables, they are really dodgy. Change to HDMI if possible.

[SparkyFX]

Cable changed to what looks like a really good quality one, now it's just turning off without me moving. Maybe David moving behind the monitor, I don't really know.

What an improvement ;-)

I had similar issues with a lightning protection in a power strip being triggered by ESD, caused by movement of the office chair on a plastic mat and rolling toward the table. I grounded the table (a metal part of it) to ground on the power strip and the issue was gone. At least the discharge seems to take a different path then.

Maybe a wiper contact to ground on the chair helps as well :-) Similar to what was used on cars for years, where i also had issues with getting a discharge when leaving the vehicle and touching the frame, depending on clothes and shoes.

Is it a monitor with a power brick or with mains connection?

[BrianHG]

How are the AC power chords wired up in you office setup?  Here in Canada, at my old house, I once used separate wall outlets and I could hear interference from static on my audio amp & occasionally get noise on my analog screens until I powered all my devices from 1 power bar.  It was not that the power bar had any filtering, it was that the GND pin on the wall outlets had separate wiring to the fuse box and the huge GND loop between the fuse box, through 2 floors of the house and the PC, then back and around again for the power chord of the monitor and speaker amp which was on a separate outlet made a gigantic loop antenna for the frame grounds and the signal video and sound cable frame ground connections and the inner cable signal grounds.  Powering everything from 1 power bar at 1 outlet shrunk the loop ground from circling the house 2 times to the length of the power cables for the PC and monitor / audio amp.  This solved a few issues.

[T3sl4co1l]

How are the AC power chords wired up in you office setup?

Major fifths, I would assume.

/rimshot

Tim

[SparkyFX]

It is an annoying problem (at least it distracts), but as long as it recovers there might be no real warranty issue for a manufacturer. One could always claim that it just takes an even larger ESD impulse to trigger problems and it is out of their control what type and size of an impulse occurs (shitstorm effects left aside). The Van de Graff generator approach is cool, but kind of implies that it is usually best to solve the issue at the source, which might be too hard for most consumers - those that recognize it as an effect of ESD kind of know what can be done or who to ask, those that don´t have a problem.

Or am i totally off and there is a standard for ESD-proofing of consumer electronics?

I mean there are several ways to harden a system, from wrapping tin foil around suspect pickup points, conductive paint in housings to other methods of grounding and shielding. Might be worth a video?

[BrianHG]

I am still surprised this is actually a problem.  HDMI should have a separate shield frame ground from PC, PC chassis, PC video card to monitor and such an expensive monitor should have shielded electronics.

I can only guess an opening in the path here is that Dave has a vanity computer case with a plastic/glass closure door where this Faraday cage frame-ground shield is broken because of that huge transparent window.

(I still don't know how those cases pass FCC...)

[SparkyFX]

(I still don't know how those cases pass FCC...)

Don´t they just check for emissions of a device, not for the device´s sensitivity?
They might even test in completely different conditions with grounded environment to exclude the person that performs the test from the measurement.

[T3sl4co1l]

(I still don't know how those cases pass FCC...)

Don´t they just check for emissions of a device, not for the device´s sensitivity?
They might even test in completely different conditions with grounded environment to exclude the person that performs the test from the measurement.

Correct, FCC does not require surge or susceptibility (they recommend it, but, alas, that's non-binding).

Most companies making dual-market products will do FCC and CE at the same time, on the same product.  CE is comprehensive, so if you're passing that, you're bound to be pretty well off even in the US.

It's nice that non-binding, foreign regulations sometimes make our lives/products better.

Note that "most companies" means a lot of small and medium quantity manufacturers.  The few big boys, are more than happy to grind out a few more cents by differentiating EMC across markets.  So, say, Sony or Panasonic and such, might make a consumer TV or camera or whatever, that varies worldwide, and are marked for certification accordingly.

Tim

[BrianHG]

(I still don't know how those cases pass FCC...)

Don´t they just check for emissions of a device, not for the device´s sensitivity?
They might even test in completely different conditions with grounded environment to exclude the person that performs the test from the measurement.

I meant the other way around.  That big glass window open to all those GHz signals on the traces and connectors of the PCBs leaking out.
Note I see how you thought that my (...) was describing external interference getting in, it's the reason why I placed that quote in brackets...

[EEVblog]

Update: I got a Display Port cable and this seems to have fixed the problem.

[SparkyFX]

I meant the other way around.  That big glass window open to all those GHz signals on the traces and connectors of the PCBs leaking out.
Note I see how you thought that my (...) was describing external interference getting in, it's the reason why I placed that quote in brackets...

Nevermind, i just recognized that i made a mistake :-), i translated/interpreted "cases" not as computer case, but as the case of ESD susceptibility of the monitor. Makes a lot more sense now.

Leads to questions of how narrow a faraday cage spacing needs to be for what signal. I think there is more focus on aspects like where the mains are connected and how well the conductive parts of the case are isolated from them and how they are grounded.

E.g. some welders tend to point out that CE style machines have the on/off switch on the back instead of the front (which is less practical), whereas this is not the case with american machines.

[PolishGandalf215]

Hello everyone, I've been having a similar situation for over 2 months. In December I purchased a new PC, picked parts at a Microcenter (MC), and had them build it since I am barely an amateur. Over a month later, when the PC cannot be refunded, I started to experience PC shutdowns when standing up from my chair (Event). Like in the video, it wasn't every time but frequent. I would have to reboot the PC from the case. One time when I was working with files in an external hard drive (EHD), the Event occurred and the EHD was fried. The PC was purchased to match my monitor, Samsung Odyssey G7 4k/144hz, and for information, I already had a Secret Labs Titan Chair. MC has been very little help but suggested using an HDMI cable, instead of the DP cable. The Event still happened and I tried about 4 different iterations of HDMI, DP, and HDMI/DP cables. I tried another copy of the monitor to see if I bought a bad monitor, Event still occurred. I am currently testing another scenario by placing my PC on a plywood sheet on 3 towels on a cardboard box on the floor. For 6 days, no Event so far, and yet I am still having ESD happen when standing up. When using my older PC, the monitor had the same black screen situation that was seen in the Shocking 4K BENQ Monitor Problem video. I was lucky enough to get a Watts Up? Pro meter hooked up to my PC to monitor (amps, watts, volts, etc.) The readings were Max Volts at 126.1 after the Event occurred/ 125 before, Max Watts 510 after / 399 before, and Max Amps 5.4 after/ 4.9 before. I haven't been able to review the data yet but will confirm what happens exactly when the Event occurs. I purchased a grounding plug and cable to ground my chair. I heard that I should get a humidifier. Any questions or thoughts on how to address this?

[wraper]

Hello everyone, I've been having a similar situation for over 2 months. In December I purchased a new PC, picked parts at a Microcenter (MC), and had them build it since I am barely an amateur. Over a month later, when the PC cannot be refunded, I started to experience PC shutdowns when standing up from my chair (Event). Like in the video, it wasn't every time but frequent. I would have to reboot the PC from the case. One time when I was working with files in an external hard drive (EHD), the Event occurred and the EHD was fried. The PC was purchased to match my monitor, Samsung Odyssey G7 4k/144hz, and for information, I already had a Secret Labs Titan Chair. MC has been very little help but suggested using an HDMI cable, instead of the DP cable. The Event still happened and I tried about 4 different iterations of HDMI, DP, and HDMI/DP cables. I tried another copy of the monitor to see if I bought a bad monitor, Event still occurred. I am currently testing another scenario by placing my PC on a plywood sheet on 3 towels on a cardboard box on the floor. For 6 days, no Event so far, and yet I am still having ESD happen when standing up. When using my older PC, the monitor had the same black screen situation that was seen in the Shocking 4K BENQ Monitor Problem video. I was lucky enough to get a Watts Up? Pro meter hooked up to my PC to monitor (amps, watts, volts, etc.) The readings were Max Volts at 126.1 after the Event occurred/ 125 before, Max Watts 510 after / 399 before, and Max Amps 5.4 after/ 4.9 before. I haven't been able to review the data yet but will confirm what happens exactly when the Event occurs. I purchased a grounding plug and cable to ground my chair. I heard that I should get a humidifier. Any questions or thoughts on how to address this?

Did you have an actual PC shutdown or what? Image temporarily disappearing has nothing to do with shutdowns.

[PolishGandalf215]

Did you have an actual PC shutdown or what? Image temporarily disappearing has nothing to do with shutdowns.
[/quote]

Yes, the PC shut down and I would have to reboot by pressing the case power button and logging back in.

[wraper]

Then why did you change video cables? It's obvious it's internal PC problem or mains power problem, like lose power cord and has nothing to do with any video cables or monitors.

[PolishGandalf215]

Then why did you change video cables? It's obvious it's internal PC problem or mains power problem, like lose power cord and has nothing to do with any video cables or monitors.

I tried the other cables based on the store's theory that the monitor was sending a shutdown signal but since it only happened when I stood up, this thread seems related but the solution was not effective. Microcenter has tested the PC itself and found no issues internally, yet they provide no report. Internal connections seem to be fine, they've shaken the PC while it's connected to their 1080p HDMI monitor to no effect. I'm gonna have them completely rebuild the PC and check the components. I now used a grounding plug to hold while I get up since I normally discharging on the chair when I stand up or light switch after I stand up. It seemed to work for a few days since there were no shutdowns till tonight while I was holding the grounding plug. Should I attach the grounding plug alligator clips to the PC and see if that does anything. I am getting various shutdown configurations where lights on and in the PC are on or off. None of this makes sense.

[wraper]

Nothing can send shutdown signal to a PC unless it's a USB HID device like a keyboard. And even then it will be a normal shutdown like if you have done it from start menu, not immediate turn off.

Should I attach the grounding plug alligator clips to the PC and see if that does anything.

What's the point? PC is earthed through mains cable.

[coppice]

Nothing can send shutdown signal to a PC unless it's a USB HID device like a keyboard. And even then it will be a normal shutdown like if you have done it from start menu, not immediate turn off.

I don't know about displayport or DVI, but an HDMI monitor port can send a shutdown command to a connected device. The HDMI ports on PC are not generally configured to react to those commands, but they do exist, and things like AV receivers are generally configured to be started and shut down by those HDMI signals from the monitor.