New installation on Dell XPS 13 9380. Flashing 4K monitor

Hi. I have just taken delivery today of the UD-ULTCDL to use with Dell XPS 13-9380, updated Windows 10, a 4k LG 27UD59 monitor and an aged BENQ monitor.

Previously I have run the LG 4K monitor as my single main monitor using a USBC- Displayport connection. Works great.
I installed the driver no problems, and connected the Docking station to the charging USB C port.
Wired Ethernet works fine, charging works, the 2 k BENQ monitor works fine. However the 4k monitor (connected to the 4k HDMI port) flashes constantly. Maybe 1 second on, 2 seconds off, and also some fine lines visible across the screen when on.
I have tried a variety of HDMI cables but these don’t make any difference.
Restarted everything, disconnected everything, but no difference.
What thoughts?


Hello Gerry,

Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

We have a troubleshooting tool that helps us find out what is going on in situations like this. Please plug the dock with your accessories attached into your computer using the USB-C cable the dock shipped with, then go to this page and follow the instructions there:

This will give is a better idea of what may be causing the issue, and we can hopefully make some recommendations on how to fix it. Sometimes issues like this can be caused by the need to install some updates, or, it could be hardware related. Worst case scenario we may try replacing the dock if nothing stands out from a software perspective.

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer | Product Owner
Plugable Technologies

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