Ud-3900pdz hdmi 1

I bought the UD-3900PDZ. HDMI 2 & 3 works fine. HDMI 1 does not.

My System Model is
GS76 Stealth 11UH (Windows 7)

System SKU

Any way to get HDMI 1 working?


Hi John​,

Thank you for contacting us, I am sorry this is not working as expected and I am happy to help!

This docking station relies on two graphics technologies to support up to three external displays.

The “Display 2” and “Display 3” outputs are controlled by DisplayLink USB Graphics Technology, this is a combination of software on the computer and hardware on the docking station which extends the capability of the computer to support more displays than the computer was designed to support. This requires installing the DisplayLink drivers for Windows ( https://plugable.com/drivers/displaylink ) or the DisplayLink Manager App for macOS and configuring macOS to support the external displays ( for macOS 13: https://kb.plugable.com/1595423, for macOS 11, and 12: https://kb.plugable.com/1185378 ).

The “Display 1” output relies on the computer’s internal graphics controller, it utilizes USB Type-C DisplayPort Alternate Mode (“Alt-Mode” for short). This is an optional USB Type-C port feature which is not enabled on all computers. This relies on the computer’s built-in graphics drivers and requires the docking station to be connected directly to a USB Type-C port with Alt-Mode capability using the original USB Type-C data cable provided with the docking station. USB Type-C cables from other products, or purchased separately online may be charging cables that do not support Alt-Mode video data.

I recommend starting by double-checking to ensure the computer is connected directly to the docking station using the original USB-C data cable provided with the docking station.

The “HDMI 1” output relies on the computer’s internal graphics controller and drivers as well, neither Intel or NVIDIA support Windows 7 on this computer’s graphics hardware, if the computer is relying on the Microsoft Basic Graphics Driver included with Windows 7 it is likely incapable of supporting an external display on the USB Type-C port.

We can check the driver versions by getting some system log files:

If you would, please keep the dock connected to the computer with monitor connected to the docking station (even though one may not be working) and attach the output of our diagnostic utility PlugDebug ( http://plugable.com/support/plugdebug ) to an email to ‘support@plugable.com’ with the subject line ‘Ticket #403225 - Attention Pat’ as this will allow us to examine some log files from your system to help determine the next steps.

Thank you,

Plugable Technology


We’re closing this thread due to inactivity, but if you have any further questions please feel free to contact support@plugable.com and we’ll be happy to help.


Plugable Technologies