Dell ST2420L - Common and Specific Problems

Your monitor has a built-in diagnostic tool that helps you determine if the screen abnormality you are experiencing is an inherent problem with your monitor, or with your
computer and video card.
NOTE: You can run the built-in diagnostics only when the video cable is unplugged and the monitor is in self-test mode.
To run the built-in diagnostics:
1. Ensure that the screen is clean (no dust particles on the surface of the screen).
2. Unplug the video cable(s) from the back of the computer or monitor. The monitor then goes into the self-test mode.
3. On the front panel, press and hold the shortcut button 1 and shortcut button 4 keys on the front panel, simultaneously for 2 seconds. A gray screen appears.
4. Carefully inspect the screen for abnormalities.
5. Press the shortcut button 4 key on the front panel again. The color of the screen changes to red.
6. Inspect the display for any abnormalities.
7. Repeat steps 5 and 6 to inspect the display in green, blue, and white colored screens.
The test is complete when the white screen appears. To exit, press the shortcut 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.
OSD Warning Messages
For OSD-related issues, see OSD Warning Messages.
Common Problems
The following table contains general information about common monitor problems that you might encounter and the possible solutions.
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 brightness & contrast controls via OSD.