I recently bought a NUC7PJYH with the intent of using it to run PLEX. I installed 16GB of G.Skill memory and had an Intel LH6i SSD laying around that I am using. I have installed Linux Mint 19 and everything is working great. The only software installed is Mint, PlexMediaServer, some remote access software (VNC and NoMachine). Everything is working well and accessing content stored on some NAS appliances. I essentially have the NUC sitting on a shelf running and have been using NoMachine and VNC (testing both) when I need to log into the box. I decided to get a small HDMI LCD display that I can hook up when needed. I got a Loncevon 10.1 inch HD TFT LCD color monitor (pretty cheap price). The monitor works fine connected to everything (other laptops, DVD player, FireTV) but not to the NUC, yet the NUC works fine connected to HDMI TVs that I have at the house. The Loncevon keeps displaying no signal no matter what I tried and I have tried using multiple HDMI cables. I am about to give up trying to use the display, bit thought that I would ask around hoping to find a solution. I am open to any suggestions if anyone have any. Thanks.
An additional note that I have not yet pursued: I can find little information regarding the Loncevon display. I suppose that I should not expect much support for a sub $70 product that is made in China and sold on Amazon. However, I did note that the HDMI specs on the devices that are successful apparently are HDMI 1.2 and I noticed that the NUC is HDMI 2.0. I am pretty ignorant of these standards and guess it is something to research.
Outputting to a display that is only compliant to the HDMI 1.2 specification should not be an issue. That said, I don't understand what is going wrong in this scenario; it should, in theory, work.
Have you tried hooking it up as a second display? Connect a TV/monitor to the HDMI connector and connect this portable monitor to the USB-C connector (you would need a USB-C-to-HDMI adapter for this).
I ended up connecting an HP 24W (budget) display which works well. Some changes were made and I went to Windows 10 on the NUC as one piece of software that I like to use is not available on Linux. I installed Windows 10 Pro and updated drivers from the Intel Support page. This evening, just as an afterthought, I tried the Loncevon display and it works good (for a really inexpensive small display). Another change that may or may not have had an effect is that I updated BIOS to JY0045.bio somewhere along the path to where the system is configured today.