Dell Troubleshooting Guide for ST2420L, ST2420LB, ST2421L, ST2421LB Monitors

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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 co

 

 

 

secure.

 

 

Verify that the power outlet is functioning properly using any other electrical equipm

 

 

Ensure that the power button is depressed fully.

 

 

 

 

No Video/Power LED on

No picture or no brightness

Increase brightness & contrast controls via OSD.

 

 

Perform monitor self-test feature check.

 

 

Check for bent or broken pins in the video cable connector.

 

 

Run the built-in diagnostics.

 

 

 

 

Poor Focus

Picture is fuzzy, blurry, or ghosting

Perform Auto Adjust via OSD.

 

 

Adjust the Phase and Pixel Clock controls via OSD.

 

 

Eliminate video extension cables.

 

 

Reset the monitor to Factory Settings.

 

 

Change the video resolution to the correct aspect ratio (16:9).

 

 

 

 

Shaky/Jittery Video

Wavy picture or fine movement

Perform Auto Adjust via OSD.

 

 

Adjust the Phase and Pixel Clock controls via OSD.

 

 

Reset the monitor to Factory Settings.

 

 

Check environmental factors.

 

 

Relocate the monitor and test in another room.

 

 

 

 

Missing Pixels

LCD screen has spots

Cycle power on-off.

 

 

Pixel that is permanently off is a natural defect that can occur in LCD technology.

 

 

Run the built-in diagnostics.

 

 

 

 

Stuck-on Pixels

LCD screen has bright spots

Cycle power on-off.

 

 

Pixel that is permanently off is a natural defect that can occur in LCD technology.

 

 

Run the built-in diagnostics.

 

 

 

 

Brightness Problems

Picture too dim or too bright

Reset the monitor to Factory Settings.

 

 

Auto Adjust via OSD.

 

 

Adjust brightness & contrast controls via OSD.

 

 

 

 

Geometric Distortion

Screen not centered correctly

Reset the monitor to Factory Settings.

 

 

Auto Adjust via OSD.

 

 

Adjust brightness & contrast controls via OSD.

 

 

 

 

Horizontal/Vertical Lines

Screen has one or more lines

Reset the monitor to Factory Settings.

 

 

Perform Auto Adjust via OSD.

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Contents Dell ST2420L/ST2421L monitor Users Guide About Your Monitor Package ContentsFront View Front Panel Controls Label Description Product FeaturesIdentifying Parts and Features Front View Back ViewLeft Side Side ViewBottom View Back View Label Description/UsePower Management Modes Monitor SpecificationsPin Assignments Pin Pin Side of the Connected Signal Number Cable DVI ConnectorModel ST2420L/ST2421L Flat Panel SpecificationsVideo Supported Modes ResolutionPreset Display Modes Physical CharacteristicsLCD Monitor Quality & Pixel Policy Maintenance GuidelinesEnvironmental Plug and Play CapabilityCaring for Your Monitor Appendix Setting Up Your Monitor Click Change Display Settings Click Advanced Settings Using the On-Screen Display OSD Menu Using the Front PanelOperating the Monitor Main Menu for non Analog non VGA Input Input Source Auto Select Brightness Contrast Back Auto AdjustVGA DVI-D Hdmi Display Settings Page DDC/CI Personalize Factory ResetOSD Warning Messages Using the Dell Soundbar Optional Setting the Maximum ResolutionClick Change Display Settings Tilt Using the TiltSetting Up Your Monitor Dell ST2420L/ST2421L monitor Attaching the Base Setting Up the MonitorConnecting the Monitor Removing the Monitor Stand Attaching the Soundbar OptionalBuilt-in Diagnostics Solving ProblemsSelf-Test Common Symptoms What You Experience Possible Solutions Common ProblemsTroubleshooting the Dell Soundbar Optional Product-Specific ProblemsBack to Contents