I (also) have video problem with my Intel NUC (NUC6i5SYH).
Im down to my second unit of this NUC and end-up with same problem.
Intel NUC NUC6i5SYH I5-6260U
2x Corsair Value Select 8GB 2133MHz DDR4 SO DIMM 260-pin
Samsung 950 PRO 256GB M.2 PCI Express 3.0 x4 (NVMe)
The first NUC unit worked great for about 3-4 weeks. Plugged into my Onkyo reciever and LCD-TV.
Then one day it gave me just a black screen when I turn'd on my system.
I work with computers for a living so I troubleshoot hell out of the damn thing.
I could'nt get the video output to work. Neither with mDP n'or HDMI.
It ended with me sending it back to reseller and use warranty.
I got money back and ordered another one..
The 2:nd NUC unit worked (yet again) about 5 weeks.....
And then one day.. THE DAMN THING.. gives me black screen.
I dont more then just power it up and watch my Netflix and off it goes. What the heck is this dudes?..
So I open up my Google and ask it what this douche-computer is all about and found out that a bunch of you Internets have the same issues, and more..
I read on and try stuff out..
1. Connect to second display monitor with mDP-DP -> no luck
2. Connect to third display monitor with hdmi -> no luck
3. Go out and buy HDMI(female)-to-DVI(male) adapter attached with HDMI-cable to NUC's and to my old'est LCD-display.
(*) at first, I wittness the bootscreen with all F-key alternatives
(*) then, just went black after a couple of seconds.. Impossible to get it display bootscreen again..
4. Update BIOS w/o display monitor
(*) download BIOS v.39 on NTFS formatted USB-stick (also tried with FAT32)
(*) LED did not blink at all..
(*) NUC did not shutdown of it's own.. So I turn it off.
(*) No luck.. still black video signal
* When I got the second unit I immedietly updated BIOS.
* Updated all drivers to latest versions from Intel download center
* I primarily want to run my NUC with HDMI
* All display montiors indicate that something is connected, but there's just nothing there..
I love this form-factor, it's perfect for my homegear so I really want to fix this.
Tomorrow I will go and buy a mDP-DVI to try with..
EDIT #1 - April 5th 2016
I connected a m-DP to DVI cabel to my NUC and my older LCD-monitor.
I got picture at first, a boot with Intel logo.
A text message: Previous boot failed would you like to restore boot?
Y / N : I choose Yes.
It self-rebooted, booted up again.. hangs at Windows 10 boot (logo). Nothing happens for 5 minutes.
I shutdown with power button. Boot it up again, black screen.......
Can't get picture again.