Plugable Thunderbolt 3 Display Port not working as expected

I have a late 2016 MacBook pro and plugable thunderbolt 3 dock. When I connect a dell p2715Q monitor to the Thunderbolt 3 port it works fine, but when I connect it to the display port on the dock if flickers and flashes on and off. Any solutions??

Hi Fred,

Thanks for posting, and I would be happy to help with your TBT3-UD1-83 docking station!

Thank you as well for the detail you provided and the troubleshooting you have already performed that is much appreciated. With our TBT3-UD1-83 dock, certain monitors may be incompatible or limited to 4K at a 30Hz refresh rate when connected through the dock’s native DisplayPort output (this is an interoperability issue between the monitor display hardware and a chip in the dock) and your Dell P2715Q monitor is known to be one of the models affected (we do our best to call this out in our product listing on Amazon and on our own website in the FAQ section ->…)

This can be worked around in some cases by changing the monitor’s internal settings to use “DP 1.1”, which will limit the display to 4K@30Hz. The manual for your monitor (…) on page 34 shows the process, which involves changing the ‘MST’ setting to ‘Secondary’. The included passive DisplayPort to HDMI adapter can also be used as an alternative connection method (along with a HDMI cable not included), which will also limit resolution to 4K@30Hz.

Finally and as you have already discovered, the display can be connected using a USB-C video cable or adapter connected to the dock’s downstream Thunderbolt 3 port (rather than the DisplayPort on the dock), which will allow 4K@60Hz functionality on an affected display.

Please let us know if that information helps or if you have any additional questions!

Plugable Technologies