Quite annoying with the nuc sometimes booting and video coming on and sometimes not. Is this an issue that is fixable or what can we do? It's fully updated firmware wise and there doesn't look to be an hdmi firmware available unless im missing it.
So im testing it with an hdmi to dvi adapter now. Just to be sure it's not the NUC. I believe it booted straight up so either the hdmi port is dead or it doesn't like to downgrade to the older hdmi version very well as the monitor is quite old now. So i'll see how it goes....
I regularly down-convert from HDMI to DVI and it works without issue. I just did a quick test of my IN NUC with HDMI to DVI adapter and it works just fine. You likely have a bad unit (this happens from time to time).
After verifying that your warranty is (still) active (here: Determine if Your Product Is Still Under Warranty), you need to directly contact Intel Customer Support to initiate the RMA process (you cannot do this through the forums). Here are pages where you can lookup contact information, including local phone numbers, by geography:
You can use the online forms service or email, but I actually recommend calling them directly. The above links provide local or toll-free numbers in most countries and support most local languages. You could also use the chat service (start here: Intel Customer Support Chat), but understand that this service is offered in English only and is subject to the normal (9:00-5:00 M-F) office hours in the Pacific (UTC-8) time zone.
Hope this helps,