Ud-3900c4 not able to get HDMI4 port working

[Loki1717]

I can only run one monitor from either hdmi3 or hdmi4. When I plug two in one quits working. HDMI1 and HDMI2 work fine but at lower resolution. I want to run two displays from HDMI3 and HDMI4

[adi]

Hi there,

Welcome to the community!

I am sorry that your UD-3900C4 is not working as expected, and I would be happy to help.

Based on the information you provided, your laptop likely does not support DisplayPort Alt Mode MST, which is required for the HDMI 3 & 4 ports to work. Can you please provide me with the make and model of your laptop? I would be happy to look into this for you.

Alternatively, you can send me your laptop system logs; I would happily review them. Please follow the instructions below if you would rather go down this route.

Please email our direct support email address ( support@plugable.com) with “For ticket # 439860” in the subject line. In the email, please include the following information:

• Please provide the Amazon Order ID number for your Plugable product purchase.
  For your reference, an Amazon Order ID number has seventeen digits (separated by two dashes), and typically that information can be found here → https://amazon.com/orders
• Can you please keep the UD-3900C4 connected to your computer (even if it is not working as expected) and send us the output of our diagnostic utility PlugDebug? → https://plugable.com/pages/plugdebug 1

This will allow me to examine log files from your computer and help determine the next steps.

Please do not post your Amazon order information or your system logs in our public forum (it contains personally identifiable information)

I hope this helps!

Thank you,

Adi

Plugable Technologies