External display randomly turns black / goes to sleep.

Kenny Millar wrote:

@den.thed Thanks for the helpful reply.

The HDMI adapter is an ULT-WIIQ from Amazon

The monitor is a Phillips 21" can't remember the exact model at the moment.

Both work well on a PC I have - with no issues at all.

The main HDMI Output from the mac mini never has an issue either.

I will try replacing the HDMI Adapter.

I'm not finding that adapter by the ULT-WIIQ reference at Amazon.

I would test one of the following adapters listed at BestBuy.

https://www.bestbuy.com/site/insignia-usb-c-to-hdmi-adapter-black/6473497.p?

https://www.bestbuy.com/site/best-buy-essentials-usb-c-to-hdmi-adapter-white/6458562.p?

FWIW I'm using the Insignia adapter on one of my Mac mini dual display setups.

Another option, is to spring for the more expensive Apple adapter.

https://www.apple.com/shop/product/MUF82AM/A/usb-c-digital-av-multiport-adapter?

https://www.bestbuy.com/site/apple-usb-type-c-digital-av-multiport-adapter-white/5596800.p?

Kenny Millar wrote:

Using an M2 Mac Mini. With one monitor on the HDMI port, and a second on a thunderbolt-4 to HDMI adapter.

The 2nd display is set up as "Use as separate display", so not using screen-mirroring.

At random intervals macOS will put the thunderbolt display to sleep (or turns it black).

No amount of mouse-movement or anything else will bring the display back on. To get it back on I put the whole machine to "sleep" for a moment and wake it back up. Both displays will now work again perfectly for some time.

The random amount of time can be anything from a few minutes to about 1-hour.

This sounds more like a faulty adapter, cable or weak connection than a sleep issue.

If it is the display on the TB/USB-C to HDMI adapter, then I would test a different TB/USB-C to HDMI adapter.

usb-c to hdmi adapter

If it is the display on the Mac mini's HDMI port, then I would test a short premium certified HDMI cable.

For more focused and accurate help, please post

the make and model of both displays

the brand of the USB-C to HDMI adapter

plus the brand and length of both HDMI cables

We agree to agree on the sleep issue problem..... 😉

However the OP states that only the one display on the adapter randomly blacks-out, which leads me to believe that this is a different problem.

At random intervals macOS will put the thunderbolt display to sleep (or turns it black).

No amount of mouse-movement or anything else will bring the display back on. To get it back on I put the whole machine to "sleep" for a moment and wake it back up. Both displays will now work again perfectly for some time.

The random amount of time can be anything from a few minutes to about 1-hour.

OK that cable adapter should work fine.

What other devices and drives do you have plugged into the M2 Mac mini's TB/USB-C ports...?

If that adapter cable is plugged into a Hub or Dock, try plugging it directly into the Mac mini TB/USB-C port.

If that doesn't help, test that adapter cable plugged directly into the M2 Mac mini's others TB/USB-C port with a minimal amount of devices plugged into the other TB/USB-C port.

There’s no need for sleep - it gets you nothing but trouble. So, disable it and save yourself a ton of aggravation. As already mentioned, for power savings, let the monitors switch off on timer. It’s different from Sleeping - unrelated entirely.

“It's OK on here to post irrelevant replies, but it is not OK to call someone out for it.”

We can agree on that 😁

By the way, Sleep used to be “normal” pre-2018, but now it’s totally…irrelevant (and aggravating, as you’re finding out). All the best!

I have a PC too, I access it with Remote Desktop and call it the Slave. Guess who’s Master😁?

Anyway, I’m out of ideas. That said, I wouldn’t re-enable Sleep - it’s a cheeky old dog, best put down. Good luck!

You're welcome.

Good. Is the Hub self-powered or buss powered...?

Yea' could be one or the combination of those device drawing too much power.

You have to experiment with different things, including using a wall charger to charge the iPhone.