External Display Screen Turns Black Randomly

Hi there, GobiDoGo.

I see that you're having a problem using your 32'' Class 4K UHD LED Monitor as a second display for your 2016 15" MacBook Pro. The monitor keeps going black every few minutes. Good job on the troubleshooting you've tried, and I'm glad to help with this.

Get help with video issues on external displays connected to your Mac -- After reviewing the information and steps under "Before you begin", scroll down to "If the display image is blank or unusable" and "Connecting displays with Thunderbolt 3 (USB-C)" for the steps to correct the issue.

Let me know how that goes.

Take care.

I have the exact same issue, the screen goes black randomly for a few seconds. MacBook Pro 15' 2018 with latest Catalina OS, closed, connected to that monitor in USB-C. I also switched the USB cable and it did not help.

Volume/brightness don't work as well (from the Mac, on the screen built-in control they work), but I guess this is more a limitation on the screen. Still would be nice that the Mac driver would allow to change that. I can change the brightness with the OnScreen Control program (from LG).

Thank you for trying those steps and getting back to us, GobiDoGo. It's appreciated. Since the external display still goes blank, it's time to contact Apple Support.

Get help with video issues on external displays connected to your Mac

"Get more help

If you've tried these steps and your display still isn't working, contact Apple Support to get more help."

Cheers!