Something I learned not long ago on this site: low quality/too long HDMI cables can make some monitors go black when the user stands or sits on a certain kind of office chair. [1] [2]
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.
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...