2

I have a problem with my new LG34WL500 monitor. When I first got it a few days ago I plugged it into my machine (Ubuntu 18.04 at that point) and it worked right out of the box. Today I tried to set it up again and I can't get the monitor to display anything. My ubuntu has been acting a bit strange anyway so I decided to reinstall the system, this time it's an Ubuntu 20.04 but still no success. If I plug the monitor in through the HDMI port it shows up in the "Displays" window of Ubuntu at once, but there's no signal on the screen. xrandr also seems to see it:

xrandr
Screen 0: minimum 320 x 200, current 4480 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 294mm x 165mm
   1920x1080     60.02 +  60.01    59.97    59.96    59.93    48.02* 
   1680x1050     59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1600x900      59.99    59.94    59.95    59.82  
   1280x1024     60.02  
   1440x900      59.89  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1440x810      60.00    59.97  
   1368x768      59.88    59.85  
   1360x768      59.80    59.96  
   1280x800      59.99    59.97    59.81    59.91  
   1152x864      60.00  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   800x512       60.17  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98  
   576x432       60.06  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected 2560x1080+1920+0 (normal left inverted right x axis y axis) 798mm x 334mm
   2560x1080     59.98 +  74.99    50.00* 
   3840x2160     30.00    25.00    24.00    29.97    23.98  
   2560x1440     59.95  
   1920x1080     74.99    60.00    50.00    59.94  
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1280x800      59.91  
   1152x864      75.00    59.97  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    60.00  
   832x624       74.55  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94

I also tried to play around with resolution or refresh frequency, nothing. I'm unfortunately not sure whether since the first try the kernel got upgraded or not.

I'd really appreciate any help, I have no idea what is going on here.

puermaris
  • 21

2 Answers2

0

I had the same problem. The monitor would sometimes be detected but would receive no signal or in other cases wouldn't even be detected. I did the following things and this fixed it for me:

  1. Change the bios mode to legacy and turn off secure boot. (Changing the bios mode made it so that the monitor would or wouldn't be detected. No idea why)
  2. Update all packages. (sudo apt update/upgrade)
  3. Changed the 'Additional Drivers'. I changed it to something that was not from NVIDIA. I noticed that depending on the bios mode, it uses a different setting for 'Graphics' (Settings>About).
  4. Rebooting lots of times and changing the bios mode to see if the monitor got a signal.

I know this isn't a great or even decent answer but this seemed to fix it for me. I hope it fixes things for you as well.

Wezzz
  • 11
-1

If you have the same problem with "No Signal" warning on external screen, just chance your nvidia settings from the link : Reinstall nvidia drivers

I tried too many solutions till now but this one is certain solution for the problem. Have a good luck.

seniorfantasist
  • 1