Dell U2421M, Troubleshooting Steps

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8. The test is complete when the white screen appears. To exit, press the Button 4 again. If
you do not detect any screen abnormalities upon using the built-in diagnostic tool, the
monitor is functioning properly. Check the video card and computer.
Common Monitor Issues
Common Symptoms
What You
Experience
Possible Solutions
No Video/Power LED
Off
No picture

Ensure that the video cable connecting the
monitor and the computer is properly
connected and secure.

Verify that the power outlet is functioning
properly using any other electrical equipment.

Ensure that the power button is depressed
fully.
No Video/Power LED
On
No picture or no
brightness

Increase the brightness and contrast controls
via OSD.

Run the monitor self-test feature check.

Check for bent or broken pins in the video
cable connector.

Run the built-in diagnostics.

Ensure that the correct input source is
selected via the Input Source Select button.
Poor Focus
Picture is fuzzy,
blurry, or
ghosting

Eliminate video extension cables.

Reset the monitor to the Factory settings .

Change the video resolution to the correct
aspect ratio (16:9).
Shaky/Jittery Video
Wavy picture or
fine movement

Reset the monitor to Factory Settings .

Check the environmental factors.