A dangling bag of coins is a famous cheap EMC test for products. All of this sounds like monitor vendors cheaped out on their EMC and need to have their ESD and Immunity certifications reevaluated....
Or maybe it's just the fact that they were dumb enough to ship an I²C interface over a cable as part of the industry spec. Never ship I²C off-board or this kind of crap happens.
Actually never heard about this before.
What is the trick? It cannot just be to shake a bag of coins next to the monitor?
We don't know who produced these cables nor where they came from. I'd wager it's mostly an issue with cheaper products, and you often don't get any cables if you're buying a cheap monitor, so they're likely from a third party.
Because part of hardware engineering is making devices that function even in poor environments, and that tolerate foreseeable misuse. (This is a major part of medical device development, for example.) Cable shielding is always iffy on consumer-grade cables. If other vendors can produce monitors that tolerate its absence, because that seems to be reasonably common!, then if you can't, your products will be seen as inferior. Exactly as is happening here.
Also dont trust all electricians. Lots of them just try and error, nod in terror. Some do not even speak the language of the e-plan they are cabling up.
So imagine all the problems you could have, and multiply it by variable frequency cable that thanks to increases in resolution has to run way higher clocks than it used to, combined with being cheapest possible design, and that unlike it's analog origins an error in bitstream can now crash the connection instead of just causing temporarily off-colour area.
Well, I guess this explains some of my "why the fuck is this even an option" when trying to make a TV just display the signal as it was received.
I've spent many frustrated minutes trying to identify if me moving was causing a cable to be pulled or such!
On the subject of interference, this is why a good amount of shop equipment doesn't use USB. Especially for vinyl cutters, serial/RS-232 tend to have less issues than USB. USB tends to be more sensitive to the static buildup caused by moving and cutting vinyl.
There’s lightning protection etc. on the circuit.
It’s worked fine for several years.
Last week, we had a huge electrical storm - and every time lightning flashed within 8km, the switch at the cabin would reboot. Unplugged, stuck a scope on the Ethernet cable - and lo and behold, 30V+ flashes every time lightning struck anywhere even remotely nearby. The cable is acting like a great big antenna.
I need it to be able to deliver PoE, which is why I went for Ethernet - but yeah, probably going to replace it with STP, although not sure that’s going to stop lightning induction in the earth/shielding. Other option is splashing out for SWA STP, which should definitely do the job.
For the other run, where I don’t need power, I’m using 802.11n with a pair of Yagis to go about a kilometre. No problems except the usual headaches around layers and discovery a Wi-Fi bridge provides.
This might explain why one of my monitors with a 2m long HDMI cable every so often fails to turn on after waking up from sleep mode
It hadn't occurred to me that cheap and excessively long HDMI cable might be a contributing factor to my AV receiver playing up.
I've replaced the cable with a much shorter one with built in ferrites both ends and haven't noticed the problems I was having.
I had a motherboard (an ASUS ROG Strix B550-E) that would frequently freeze when I stood up from my chair. I always figured it was something to do with static electricity discharging when I stood up, but no amount of fiddling with grounding helped. An EMI pulse from the gas lift getting picked up somewhere insufficiently shielded would explain it.
Interestingly, I also have a Steelcase Leap chair, as mentioned by someone else in this thread; maybe the gas lift they use is particularly prone to this? Other people also complained about freezes with this motherboard model, so perhaps the combination was particularly bad.
Apparently it's a known issue at Dell: [3]
>Surprisingly, we have also seen this issue connected to gas lift office chairs. When people stand or sit on gas lift chairs, they can generate an EMI spike which is picked up on the video cables, causing a loss of sync. If you have users complaining about displays randomly flickering it could actually be connected to people sitting on gas lift chairs. Again swapping video cables, especially for ones with magnetic ferrite ring on the cable, can eliminate this problem. There is even a white paper about this issue.
[1] https://www.youtube.com/watch?v=voW5kEI7JKE
[2] https://www.youtube.com/watch?v=D6pY4t0k1hk
[3] https://support.displaylink.com/knowledgebase/articles/73861...