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An external LCD does not show a picture when connected to the HMDI to VGA adapter.

Dell Latitude 7490
OS: Windows 10 version 1909

Issue: An external LCD does not show a picture when connected to the HMDI to VGA adapter.


In Intel display properties the second monitor appears.

In Device Manager, Monitor, the second LCD appears


I installed updated video drivers and will see what will happen, soon.

My next step is to just  remove the Intel drivers and see if the Microsoft drives allow me to see a picture on the external LCD.


I confirmed that the second LCD or monitor is appearing in Windows 10 display properties: I see two squares, one for each LCD.
Since the laptop is remote, I did not bother to make the external LCD the default monitor
I did not close the lid to see if the picture show on the external LCD

The 19 inch LCD is working correctly.

Changing the resolution of the external LCD did not help: I tried Windows 10 recommendation resolution
Note: Windows 10 scaling and layout is set to 100% ( I suspect this could be the root cause of the problem)

Other things I can try is to update Windows 10, may it is a bug in Windows 10 version 1903.

Research: https://answers.microsoft.com/en-us/windows/forum/all/external-display-and-audio-problem-windows-10-home/f7171a5c-13a9-48fe-96d5-fe6835184848
https://answers.microsoft.com/en-us/windows/forum/all/lenovo-carbon-x1-laptop-does-not-detect-monitor/a32cd13e-bf4c-44c1-bf2f-c54d948f442f

I will have to update the BIOS and run a hardware diagnostic test, before contacting Dell to replace the system board.
Moreover, I should update the chipset drivers, since I have seen a similar problem when a laptop with the same model was connected to a docking station.
Maybe the problem was caused by a recent Windows 10 update and I should roll back the drivers.

Question: Can someone please explain to me what happens when an external LCD is connected to a laptop, for instance, what services are in use.
Windows 10Dell

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M

8/22/2022 - Mon
David Johnson, CD

did you tell it to use the 2nd monitor i.e. mirror/extend  
Windows + p will allow you to change it.
SOLUTION
Kimputer

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ASKER
M

David,

Yes, I have selected duplicate display and extended, neither showed a picture.

Kimputer,

On another laptop with the same problem, I had replaced the HDMI to VGA adapter with a HDMI to DVI adapter, and the problem still remains.
I even replaced the LCD.  The docking station (Dell WD15) remained the same.

All thank you for your input.
Kimputer

So you tested it throught the WD15? Or through the laptop itself?
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Robert Retzer

I have run into this problem before, try updating the firmware on the WD15 and update the bios of the laptop to the most recent version. 
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ASKER
M

Kimputer, I tried a different resolution, based upon what you were suggesting. For some reason, the recommend resolution did not work.
ASKER
M

All,

The problem is resolved in one instance. In a second case, it was not resolved, I recently updated the Dell WD15 firmware, the issue is still not resolved.
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Kimputer

Besides changing resolution (since it's probably not correctly communicated to Windows), make sure that the refresh rate (Hz) is also not exceeded above specified by the monitor in question. Usually 60Hz max.
ASKER
M

Robert R,

The firmware on the docking station was updated, but I did not restart the system afterwards to test.

The next plan of action is to send the laptop to Dell for repairs.

I just remember that the system board was replaced in the past and there is a BIOS settings: POST Behavior, Select - Fastboot the select the Thorough option