I'm having a terrible time with HDMI on my new NUC. Hours of searching and research have revealed others having similar issues, but those threads always seem to end without resolution. Frustrating.
I have the NUC7i5BNK J31144-309 HDMI port connected to an HDMI 2.0 port on a new LG43UD79 4K monitor 3840x2160 30Hz, Win10 display scaling either 100% or 150%. The NUC BIOS is updated to latest BNKBL357.86A.0063.2018.0413.1542, and I have tried setting the BIOS default display to either AUTO or HDMI. I have simultaneously removed both drivers, rebooted, and let Win10 re-install them. They are the latest available (April 6) versions including Intel(R) Iris(R) Plus Graphics 640 version 24.20.100.6025 and Intel(R) Display Audio version 10.25.0.5.
My NUC is set never to sleep. Whenever the monitor is blanked and turned off, or if the input source on the monitor is switched to another computer, there is no audio when the monitor is restored. The volume control system icon reliably has a red 'x' on it, and there is no corresponding playback device. Going to the Device Manager for Intel(R) Display Audio and using Disable followed by Enable sometimes resolves the issue. Other times, a reboot is required.
This is evidently a long term problem that has not been addressed by Intel but should be easy to reproduce. I also have the problem of all windows getting shrunk to the upper left all the time, but the audio problem is pretty much a show stopper for trying to replace my 8-year-old old Win10 tower with a NUC. System Support Utility output is attached. I could really use some suggestions for things I haven't tried yet.
Thanks,
Curt