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

[TequilaYeun]

1. Hongo P156A06

2. Monitor has 2 SS ports, I have tried using both

3. Yes, attempting to connect via Thunderbolt cable directly between monitor and laptop

4. Windows does not detect a second display when only using USB-C cable

5. No, device manager shows Integrated Monitor only

6. I did not receive an HP USB-C cable, but I have tried multiple cables

7. I have tried both battery and AC, but neither one works

So far the only thing that works is plugging AC into the monitor and then connecting monitor to laptop via USB-C

[Deep_World]

Hi @TequilaYeun,

Based on what you've shared, the most likely cause is that the monitor requires more power than the USB-C port on the HP EliteBook 6 G1a can provide while simultaneously sending a video signal. Since the monitor works immediately when external power is connected, the monitor and USB-C video functionality are likely working correctly.

Simple Steps to Check

1. Update BIOS and USB-C Firmware
   • Visit HP Support and install the latest: 
     • BIOS
     • Chipset drivers
     • USB-C/Graphics-related firmware
   • Restart the notebook after updates.
2. Test the Other USB-C Port
   • If your EliteBook has more than one USB-C port, test each port individually.
3. Connect the HP Power Adapter
   • Connect the notebook's AC adapter.
   • Then connect the monitor using only the USB-C cable.
   • This ensures maximum power is available to the USB-C ports.
4. Use External Power for the Monitor
   • If the monitor continues to work only when powered separately, this confirms the monitor requires additional power beyond what the notebook can supply over a single USB-C connection.

Because the monitor works with external power, Windows does not detect the monitor when powered only through USB-C and Multiple cables and ports have been tested,

this points to a power delivery limitation or compatibility issue between the monitor and the HP EliteBook's USB-C implementation, rather than a driver or Windows problem.

If BIOS and firmware updates do not change the behaviour, the practical solution is to use external power for the monitor or a powered USB-C dock/hub. Unfortunately, there is no Windows setting or driver adjustment that can force the monitor to operate on a single cable if the required power and video negotiation cannot be established between the two devices.