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Intel boxnuc715bnh Issues getting Display port or HDMI over lightning/USB-C

Hi All,

First time posting, long time system builder but I honestly can't explain these issues. I just set up this nuc with Windows 10 home, an M2 SSD and all works well with my primary monitor coming over HDMI - on attempting to set up a second monitor over the lightning port I can't get it to work: Attempts/results below. Pls advise. Thanks.

# 1: USB-C to HDMI adapter. Tried to get a cheap belkin-like USB-C to HDMI adapter, plugged one end into the lightning port on my NUC, the other into my monitor - I have <10s of video flash up on the screen then it cuts off. Attempted this on both monitors, same result. Suspect it may be a faulty adapter but not sure.

# 2 - Displayport over USB-C. I read in the manual that the lightning port also natively supports displayport, so I purchased a USB-C -> DP cable, which caused all sorts of weird things to occur. After ordering a cable and plugging it in I had 30ish seconds of video, before the screen cut out. This wasn't just a 'turn it off and on again' style error either- after I removed the cable, it wouldn't even let my monitor power on again! After unplugging the monitor from power for 30s, I was able to power the monitor again after plugging it back into power.

Isolation tested this with both of my monitors, exact same results with both methods each time. Is there a driver upgrade or BIOS change necessary to make this work? These two monitors are workhorses and have never failed me until today when I attempted # 2. Honestly stumped. Any ideas? Thanks.

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Super User

I am using this on a nuc7i7bnkq and it works flawlessly (and without flaw!): USB-C to HDMI Adapter - 2-Port MST Hub | USB-C Video Adapters |

Driving both monitors has never failed.


Super User Retired Employee

First of all, what are the monitors that you are attempting to use?

Secondly, let's be clear: this is not a Lightning port; it is a USB-C port with Thunderbolt 3 (TBT 3) support. You should not mix up the names as that could lead you to grief. A subtle difference between this port and a pure TBT port is that, while you can connect two monitors to a TBT port using a TBT hub, this won't work on the USB-C port. As Al (Doc) has (inadvertently) pointed out, to connect two monitors to this port, you need to either use a MST hub or use DisplayPort (DP) daisy-chaining. Secondly, two monitors connected this way would be sharing the bandwidth of the single DisplayPort (DP) interface. If you are using two 4K monitors, this means 30Hz is the best you can do (but two 1080p monitors can run at 60Hz no problem).

Ok, back off that tangent. I would normally blame the first result on a crap adapter. The second result could also be a crap cable, but it feels like there's something else going on here. It almost seems like a ground loop is forming (which could need an A/C power disconnection to clear). Unfortunately, because it could still be a crap cable, the only way to know for sure is to get a known-good, quality adapter (either HDMI or DP) and try it (the one Al is using is a good one). If it doesn't work, I would consider having the NUC base unit replaced.

Hope this helps,



Thanks all, I just decided to stop messing around and invested in a simple Samsung EE-HG950 USB-C ->HDMI adapter. Plug and play, worked without a single hitch. I could run multiple screens off the USB-C with a different hub, but happy to stick with HDMI for my primary and the USB-C adapter for my secondary (I hadn't even considered daisy chaining.. but being a Linux/Windows guy I've never kept up to date on the display port standards) and don't need over 1080p either way at this stage, its only an old pair of dell 24" LCD panels, nothing fancy.

@Scott, thanks for the clarification RE the TH/USB-C connection, I just skimmed the manual and hoped this connector would work OOB. Honestly your talk about the short sounds spot on - you get what you pay for unfortunately and cheap cables from china will deliver on price but not much else.