Mac Mini (M1) 2020, LG UHD monitor flickers on dark colours.

I have just moved down to my French house. My M1 Mac Mini was connecting perfectly to a 1080P Philips TV in the UK but when I try to connect it to my Philips TV (nominally a 4K TV but only on HDMI #1 whereas I am using HDMI #3, which is only a 1.4 input the screen flicks off and on every few seconds. I have tried all different screen pitches and refresh frequencies with no change. Just as an experiment I plugged it into HDMI #1, the 2.1 port and it did exactly the same. My old Mac Mini worked perfectly. I am reluctant to buy a USB-C to HDMI so that I can use my M1 Mac Book Air with the TV, as I suspect I might get the same fault. I have been into the TV's toolbox and set HDMI #3 optimised for computer which made zero difference other than altering the colour balance to a higher temperature. When the actual picture is showing in between black outs, it is just fine.

Any more ideas folks

Wilson

I have the exact same problem with a DELL S3221QS, which worked perfectly with my previous PC.

It's especially bad when the dark mode is toggled on or when I'm watching TV shows with darker scenes.

I've also tried multiple different cables and connectors, monitor settings etc., but nothing really fixes the issue.

How come this still hasn't been fixed or at least addressed after such a long time? The new M1 Macs made me want to give macOS a chance and I've been really enjoying it, but this issue does leave a bad taste in my mouth...

Amazingly, my M1 Mac Mini and my Philips 4K TV sorted the problem out between each other, without my intervention. I left them connected and running overnight and when I looked in the morning, the problem had sorted itself out. Now have no flickering or black outs and have been able to watch F1 TV on Google Chrome (did not work on Safari), for F1 practice for the Belgian GP at Spa, with no problems. Yes I am very puzzled too. Problems do not normally sort themselves out. Oddly on looking back at the M1 Mac Logs on Console, I found the Mac Mini had restarted itself during the night after a kernel panic and I wonder if restarting the Mac with the TV connected, enabled the two systems to talk intelligibly to each other.

Another update from my end:

The replacement main logic board was still defective right out of the box! AASP replaced the other defective "replacement" MLB, and yet the replacement (2nd replacement) is also defective and it has worse issue out of the box--flickering lines are more obvious than before even on light areas (and dark areas of the screen). So that makes it 3 defective MLBs (original MLB, 1st replacement MLB, and 2nd replacement)--a strikeout!

May Apple have mercy on us!

A good information would be to tell us which frequency you set, because on 30Hz, I get headaches and is a big NO from me. I paid for 60Hz monitor and mac and I shall use it at least on 50Hz if possible.

Maybe, just maybe, the problem is with the internal power supply (prolly not supplying the correct voltage, amperes, etc. to the MLB? After 3 MLBs, problems still persistent (confirmed by my AASP). Apple did not replace the power supply.

I just don't know.

Hello,

I just received an LG 32UN500 and same thing: flickering when some sudden color changes (i.e. on fullscreen YouTube videos when there is text on screen). I changed to RGB and seems better but it is still there.

I can still ask for a refund for the monitor, but it is good for its price. Is there any updates on this issue? Any working fix?

Thanks

Same problem here with a Dell 3221QS and Macbook Air M1 base model.

Managed to change the signal from YCrCb to RGB, which makes a slight improvement but it is still there. I've also found USB-C to HDMI works better than USB-C to DP, which would actually cause the screen to black out completely.

[Edited by Moderator]

Gengar, Turning on HDR does fix the issue.. but it might have washed out colors. I have the same issue and turning on HDR from Display preferences fixed it. Id recommend downloading the ICC Color profile to get your HDR colors back

OK I fixed my monitor!

Few days ago I purchased new Asus ROGXG27UQR and replaced my old 27" Dell on USB-c to DP connection. My old 24" 4K got new HDMI cable that was supplied with Asus monitor and now I have 0 flicker and 0 problems!

Now I can run my 24" Dell on 60Hz and Asus monitor on 144Hz without a single problem on my M1 mini and macOS Monterey is also working (I updated 1 week after switching cable so both 11.6 and 12.0 versions work).

To sum up: check your cables. They might work and everything, but they might have poor insulation and protection. Invest in good cables, specially HDMI seems to be very delicate. Also HDMI cable needs to support HDMI2.1as 2.0 has only 18Gbps and for 4K monitor on 60Hz it is needed around 19Gbps bandwidth. On 2.0 will work, but only in perfect conditions (probably if you use RGB instead yPbPr).

Hi I am facing exactly similar issue. I thought it was my Acer nitro monitor and got it replaced today but I am still facing this issue. I randomly see gray lines all over my screen and there are traces of previous screen on my home screen too. It eventually fades away after sometime. Does any one has a solution to this? is this a known issue with Apple mac mini M1? or it is my screen? Also can someone post a picture of how it looks? I am attaching mine.

This is how it looks on my Dell 3221QS and Macbook Air running Montery 12.0.1. Connected over HDMI in RGB mode (YCrCb is far worse and DisplayPort is even worse) at 3840x2160 60Hz.

https://imgur.com/a/tzYkrfS

MacBook Air M1 + Montery 12.0.1 + Zikko Thunderbolt4 cable M-TB4200 (2 Meter) + HYPERDRIVE GEN2 16-Port Docking Station + BenQ Manufacturer Thunderbolt3 cable (0.8 Meter)+ BenQ PD3220U

My new BenQ PD3220U has a similar problem of ghosting and flickering after a month of use. I contacted the BenQ manufacturer and learned that it was the cause of M1.

I have the exact same issue with a Macbook Pro M1 (2020) and an external Lenovo T34w-20 Ultra-Wide monitor.

FWIW, I just realized that changing the monitor color profile to "Custom", the problem is gone as long as I keep the "Blue" value at 98% or lower. Just like flicking a switch.

This will probably not work for everybody, but hopefully it will for some.

Replying to myself here, because I realized that what causes the problem to go away, is actually some combination of parameters. Using a preset color profile (reddish) that shows the problem here, the problem disappears when raising the contrast above 48. So you may need to try a few things to make it work. Good luck. :)