External USB-C screen keeps connecting and disconnecting non stop

[jornhd]

I recently bought LG 35WN75C-B, a monitor with USB hub and USB-C power delivery. I wanted this monitor to be able to dock the laptop using the USB-C cable only. Unfortunately it doesn't work properly. When I plug it in, the monitor connects along with the mouse and keyboard connected to it, but then after 2-3 seconds it disconnects. 2 more seconds, and it connects again, and this keeps going on. When this  happens I get this message in the Windows event log: "PowerEvent handled successfully by the service" from the source "HP Comm Recovery".

In 2 occasions, I've got it to work properly with everything working, and battery charging as well. Both times was just after a reboot, I've tried to replicate this many times after I first got it working this way, but with no luck.

I'm using the USB-C cable that came with the monitor. I also bought a new high quality Belkin cable that is rated for 100W power and 4K audio/video to try see if the original cable was bad, but the same thing happens with this the Belkin cable.

I've installed all the updates available in HP Support Assistant and Windows 10. I've also tried to disable power management in the extensible host controller as suggested on various sites. I've even tried connecting the monitor with nothing in it's USB hub. Now I'm clueless to what to try next.

I know the monitor is not the problem, because I've tested it successfully with 3 other laptops.

Can anyone help me to get this working?

[The_Fossette]

@jornhd

I reviewed your post and I understand that the external monitor connected via USB C port keeps disconnecting.

Don’t worry, I assure you I will try my best to get this sorted.

I recommend you update the BIOS and the graphics driver from the below link and check whether the issue is resolved.

BIOS: https://ftp.hp.com/pub/softpaq/sp112501-113000/sp112804.exe

Graphics: https://ftp.hp.com/pub/softpaq/sp111001-111500/sp111087.exe

Let me know how it goes and you have a great day!

P.S: Welcome to the HP Support Community 😊

If you wish to show appreciation for my efforts, mark my post as Accept as Solution. Your feedback counts!

Cheers!

Stay Home – Stay Safe

[jornhd]

@The_Fossette

Thank you for responding! I've installed both updates now, but unfortunately it didn't help. The problem persists. 

[The_Fossette]

@jornhd

I recommend you contact support to further diagnose the issue.

Here is how you can get in touch with support.

1)Click on this link – www.hp.com/contacthp/

2)Select the product type.

3)Enter the serial number of your device or select let HP detect your product option.

4)Select the country from the drop-down.

5)You should see the HP phone support number or Chat option listed.

Cheers!

[Undisclosed]

I have the same issue with my 2020 HP Envy x360 15 Inch laptop. I am using a Dell U2721DE USB-C hub monitor. I have taken the same steps that you have completed with no resolution for the disconnect/reconnect issue. I have even sent it in for warranty repair, where they replaced the mainboard and other parts but, I am still having the same issue.

I also have a 2019 HP Envy x360 15 Inch laptop that does NOT have the USB-C disconnect/reconnect issue when connected to the same Dell U2721DE USB-C hub monitor. As you mentioned in your post, it's not the monitor, it's the laptop.

At this point I am considering returning the 2020 HP Envy since I am unable to resolve the USB-C hub issue. I am very disappointed with HP. 

[Undisclosed]

I have not had any luck resolving the issue even with a new wire. I will definitely be returning the laptop at this point.

This is the new USB-C to USB-C cable I tried it with:

USB-IF Certified Cable Matters USB4 Cable with 40Gbps Data, 8K Video Support, and 100W Charging in 2.6 ft - Fully Compatible with USB-C, Thunderbolt 3, and Thunderbolt 4 - ( https://www.amazon.com/Certified-Cable-Matters-Support-Charging/dp/B08Q79BY1X/ref=sr_1_5?dchild=1&ke... )

[KW852456]

I am also having the same issue. The external monitor (Dell) will often flicker on and off but the other connections such as audio, mouse works perfectly fine even when the monitor loses visual display. 

Is there a solution to address this USB C? Grateful if anyone can help.