09-19-2019 11:24 AM - edited 09-19-2019 11:33 AM
Recently I bought a Dell U2719DC monitor and tried to connect my T480s (20L7002LCD, i5-8250U, MX150) via Type-C cable. Sadly I found I encountered a severe monitor flickering issue: every few minutes, the external monitor will blackout for around 2 seconds and come back, which really distracted my attention. This behavior can happen at any time any rate, but I find it can be especially frequent when watching some Youtube videos. One such video is Test video. In that case, the monitor will become nearly unusable.
Here's what I have tried to mitigate the problem:
1. Install any Offical Intel Graphics driver of major version 26 (25 or before is not supported by Windows 10 1903), and Lenovo's manufactured driver for T480s. Not work.
2. Install the latest, OS preferred, and Lenovo's own NVIDIA Graphics driver. Though I believe this is not an NVIDIA issue since I can reproduce the problem even after the MX150 is disabled from device manager. Not work.
3. Update the monitor (U2719DC)'s firmware. Not work.
4. Of course, the OS and other drivers had been updated to the latest version through Windows Update and Lenovo Vantage software. Note that includes BIOS update and TB3 update. Not work.
4. I have checked and confirmed it's not a monitor or cable issue. I have another laptop and it worked totally fine.
During the process, I find this problem has a weird behavior. The flickering issue will only happen when BOTH of the two following condition is met:
1. The project mode is set to "Second screen only"
2. The external monitor's resolution is set to 2560x1440.
It means if I set project mode to Extend, which both of the internal display and the monitor is up then no flickering will happen; Or, If I set the external monitor's resolution to 1920x1080 in "Second screen only", everything is fine.
Now during the post, I'm using the Extend mode to overcome the issue. I have to open up my laptop although I don't need its screen. If anyone has an idea about it, it will be really appreciated.
System information: Windows 10 Pro 1903 (Build 18362.365), Intel Graphics Driver 18.104.22.16807, NVIDIA Graphics Driver 22.214.171.12440, BIOS Firmware N22ET57W 1.34.
10-23-2019 02:41 PM
Welcome to the community forums.
Have you tried connecting the monitor without the dock? Are you experiencing the same problem using another connection (i.e. VGA/DP)? Could you check for updates using the Lenovo Vantage and install all updates available? Let us know how it goes.
10-25-2019 03:31 AM
Thanks for your reply!
1. Have you tried connecting the monitor without the dock?
I'm not using the dock. The monitor directly connects to the laptop using a type-c to type-c cable.
2. Are you experiencing the same problem using another connection (i.e. VGA/DP)?
Yes. T480s do have an HDMI port. The problem resists on the HDMI.
3. Could you check for updates using the Lenovo Vantage and install all updates available?
Yes. All the drivers have been upgraded to the latest version as they could be. Even at this moment, the problem could reproduce.
This problem is not that common, and I'm really appreciated for any help.
10-25-2019 10:45 AM
This might caused by insufficient power supply from your ThinkPad 480S. Kindly check the battery settings if it's set on High Performance, change the power options:
Observe if the issue persist when the laptop is plugged in or in battery mode.
11-03-2019 09:09 AM
11-03-2019 12:55 PM
Hi! Just to make sure you have the updated firmware, could you provide to us the BIOS version of the laptop and the current Windows 10 OS version running on your system?
11-03-2019 01:02 PM