External monitor connected going black for a second few times a day.

[palba]

I have this problem with a MacBook Pro 8,1 (through Thunderbolt port), a Mini display port to HDMI cable (a cheap one sold by Amazon Basics), a monitor DELL S3221QS (32'' - 4K Ultra HD). Same problem (as far as I remember) with a Mini DP to HDMI cable and a HDMI cable or a Sony HDTV. The screen becomes black for one second, this can occur every ten seconds for one minute and then not occur for hours. If I move the plugs slightly, I do not see the problem: it is not bad contact. My Mac runs Ubuntu 22.04.

I become aware that I could use the Display port instead of the HDMI port of the monitor.

 

[MacMan988]

I have the same issue. It started almost an year ago and hasn't been fixed yet.

 

[ecarin]

I fixed the problem with an easy solution!
the problem is with ground.
how to fix? Just tape around the HDMI cable with electrical tape(I don't know if other tapes work) and carefully cut the extra part of tape to the HDMI edges with a blade.(only the side that is connected to macbook HDMI port)
I attached a file!

 

[Rhyalus]

It's the cables. Same thing happened to me with windows laptops. If you are running at a high refresh and you have a sub-par cable, it will happen. And DisplayPort is better than HDMI... you need to spend money on the cables.

R

 

[ecarin]

It's the cables. Same thing happened to me with windows laptops. If you are running at a high refresh and you have a sub-par cable, it will happen. And DisplayPort is better than HDMI... you need to spend money on the cables.

R

Can I use a Hub and then connect the HDMI cable to Hub via thunderbolt?

 

[Rhyalus]

Can I use a Hub and then connect the HDMI cable to Hub via thunderbolt?

I do this on one of my computers, but it really depends on how picky your monitor is and the quality of the cables and the hub. I have a 2k monitor that can do 165Hz, but with HDMI I think it can only do 120hz - and I could not go through a powered USB with a stable signal.

This is a little off topic but good reading. https://www.cablematters.com/Blog/HDMI/does-HDMI-support-240hz

Regards,
R