External Monitor Not Connecting via USB-C Cable

[TequilaYeun]

I have a Hongo external monitor that would connect via one usb-c cable with a Lenovo laptop (it still does, recently tested)

The same monitor will not connect to my HP Elitebook 6 G1A 14 unless there is an additional power source powering the monitor. When plugged in with the cable only, the monitor powers on, but says "No Signal"

I have updated drivers, reset display drivers, Win + P

I have a Thunderbolt 4 cable that I have been using

I would prefer not to carry two chargers, one for my laptop and one for my monitor, if possible

[Hawks_Eye]

Hi @TequilaYeun 

Welcome to the HP Support Community! We're here to help you get back up and running.

I understand that your Hongo monitor is able to display video and receive power through a single USB-C connection when used with another notebook, but with your HP EliteBook 6 G1a 14-inch Notebook AI PC, the monitor only shows a "No Signal" message unless an additional power source is connected.

Since the monitor powers on when connected to the EliteBook, power delivery is present. The behavior suggests the video signal may not be successfully negotiating over the USB-C connection, or the monitor may require more power than the notebook is able to provide while simultaneously sending a display signal.

To help isolate the cause, could you please confirm the following?

1. What is the exact model number of the Hongo monitor?
2. Does the monitor have multiple USB-C ports, and if so, which port are you using?
3. Are you connecting directly between the monitor and the notebook, without any dock or adapter?
4. In Windows Settings > System > Display, does Windows detect a second display when only the USB-C cable is connected?
5. When the monitor is connected without external power, does Device Manager show any new monitor entry under "Monitors"?
6. Have you tested the HP-provided USB-C cable (if available) in addition to the Thunderbolt 4 cable?
7. Is the notebook powered by its AC adapter during testing, or running on battery?

Based on the information shared so far, one area worth checking is USB-C power allocation. Some portable and USB-C-powered monitors require a specific level of power while also receiving DisplayPort Alt Mode video. 

If the monitor's power requirement exceeds what can be supplied through the USB-C connection in that configuration, the monitor may power on but not complete the video handshake until external power is connected.

Once you share the monitor model and the results of the checks above, we can provide more focused troubleshooting steps to help determine whether the issue is related to USB-C video output, power delivery negotiation, firmware, or display detection.

Take care, and have an amazing day!

Regards, 

Hawks_Eye