Precision 7720 only recognizes 2 out of 3 external monitors
I am having issues connecting three monitors to my Precision 7720 laptop. Due to the limited number of display ports on the workstation, my configuration is as follows:
1 ASUS VH232H connected via a 'USB-C Thunderbolt 3-to-HDMI adapter'
1 ViewSonic XG2402 connected via a 'Mini DisplayPort-to-HDMI adapter'
1 LG 34UM61-P connected via HDMI
When I attempt to connect all three monitors, the monitor connected to the mini displayport is no longer detected. If I unplug any of the connectors, the other two monitors function as intended. The same occurs whether I have the laptop lid closed and/or manually disable the laptop display through Windows display settings.
Is there some way I can force the laptop to feed the digital output that is intended for the built-in display to one of the external monitors? I would rather work with 3 external monitors and no built-in display rather than 2 monitors and 1 built-in display.
If that is not possible, would a USB-to-VGA in place of one of the other display adapters solve the problem? (I'd rather not spend the extra for a USB-to-HDMI since it's just for work).