Expertbook B9400CEA: No signal to external monitor through USB-C / thunderbolt connection

[tkhfung]

System: Windows 11, Firmware 311
Battery or AC:
Model: Expertbook 9400CEA
Frequency of occurrence:
Reset OS:
Screenshot or video:
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Detailed description：I have a LG 29" monitor with both HDMI, DP & USB-C input ports at the back. I can connect it to my expertbook through the HDMI port no problem, but when I use the USB-C to thunderbolt connection, the external monitor does not receive any signal.
The monitor can detect that I've made a physical connection with the thunderbolt, and asks if I would like to switch from HDMI, but when I do switch, there is a black screen with no video input.
On the laptop end, it can also sense that I've connected the thunderbolt to a monitor, as the charging icon shows up over the battery, but I cannot get any video to display on the external monitor if I specificially select screen mirror / extension.
I've ensured all the USB controller & hosts drivers on the laptop is up to date, but the problem persists.
Any advice?

[Falcon_ASUS]

tkhfung

1. System: Windows 11, Firmware 311
2. Battery or AC:
3. Model: Expertbook 9400CEA
4. Frequency of occurrence:
5. Reset OS:
6. Screenshot or video:

========================

Detailed description：I have a LG 29" monitor with both HDMI, DP & USB-C input ports at the back. I can connect it to my expertbook through the HDMI port no problem, but when I use the USB-C to thunderbolt connection, the external monitor does not receive any signal.

The monitor can detect that I've made a physical connection with the thunderbolt, and asks if I would like to switch from HDMI, but when I do switch, there is a black screen with no video input.

On the laptop end, it can also sense that I've connected the thunderbolt to a monitor, as the charging icon shows up over the battery, but I cannot get any video to display on the external monitor if I specificially select screen mirror / extension.

I've ensured all the USB controller & hosts drivers on the laptop is up to date, but the problem persists.

Any advice?

Expertbook B9400CEA: No signal to external monitor through USB-C / thunderbolt connection

@tkhfung
Have you tested other cables?
If the other cables are replaced and the condition remains the same, I would suggest you bring back your laptop to our service center.
The following is the contact information: 
http://www.asus.com/support/Service-Center-All-Countries/
Also you can contact the local service center for help. The following is the contact information: 
http://www.asus.com/support/CallUs#
Sorry for any inconvenience it may be caused. 

[Rora]

I think you need to check the settings because sometimes that might be the problem. But if that doesn't help, I recommend you to contact a professional who will definitely be able to help you.

[kukuriga]

Rora

I think you need to check the settings because sometimes that might be the problem. But if that doesn't help, I recommend you to contact a professional who will definitely be able to help you.

View post

 I had an old monitor for a long time, and then one day, it went out and wouldn't turn on anymore. I went to a mechanic, and he explained that the monitor was too old and pointless to repair it. So I decided to buy a new monitor for work. A friend of mine advised me to buy a great monitor, so I did. The new monitor was much more comfortable to use.

[ASUS_Bot]

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