Dell P2421D Monitor Usage and Troubleshooting Guide
Summary: Learn how to setup and use Dell P2421D monitor. Find troubleshooting instructions for common video or display issues.
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Symptoms
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Quick LinksGetting Started with your Dell Monitor Dell P2421D Setup, Specifications and Service Manual Dell Drivers & Downloads Warranty & Support Services Frequently asked questions |
Cause
For help with video or display issues such as: no video or no display, blank or black screen, flickering, resolution or color issues, horizontal or vertical lines, etc. refer to an expanding section below.
Resolution
The key features of Dell P2421D monitor are:
- 2560 x 1440 resolution, plus full-screen support for lower resolutions.
- Tilt, swivel, height, and rotate adjustment capabilities.
- Digital connectivity with DisplayPort and HDMI.
- Equipped with 1 USB upstream port and 4 USB downstream ports.
- Plug and play capable if supported by your computer.
- 0.3 W standby power when in sleep mode.
- Optimize eye comfort with a flicker-free screen
- Security-lock slot (optional)
Warning: The possible long-term effects of blue light emission from the monitor may cause damage to the eyes, including eye fatigue or digital eye strain. ComfortView feature is designed to reduce the amount of blue light that is emitted from the monitor to optimize eye comfort.
This section provides some specifications of the Dell P2421D monitor. To learn more about the specifications of Dell P2421D monitor, refer to the User's Guide at the Dell Manuals website.
| Panel technology |
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| Maximum resolution |
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| Viewing angle |
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| Contrast ratio |
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| Response time |
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| Color gamut |
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| Color depth |
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| Ports and connectors |
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Ensuring that your Dell monitor is set up properly - assembling the monitor stand and setting up the monitor ergonomically, connecting the cables and organizing them, will only help make the viewing experience the best it possibly can be.
Attaching the stand
The standard monitor stand is detached when the monitor is shipped from the factory. To learn more about attaching the standard monitor stand, refer to the Setting Up the Monitor section in the User's Guide of your Dell P2421D monitor.
To learn how to set up any other stand with a monitor, refer to the respective stand setup guide for setup instructions.
CAUTION: Do not remove the monitor from the packaging box before attaching the stand.
NOTE: The Dell P2421D monitor weighs 7.29 kg (16.07 lb) with packaging; handle with extreme care.
Ergonomics
Where you put your monitor is almost as important as what model you buy. The monitor should be directly in front of you, at an arm’s length away (between 20-40 inches from your eyes), with the top edge of the screen at eye level when you are sitting comfortably. You may need to adjust your chair height or the height of the monitor to achieve this.
Connecting your monitor to the PC
To connect your Dell P2421D monitor to your PC:
- Turn off your PC and disconnect the power cable.
- Connect the DisplayPort or HDMI cable to the corresponding video or display port on the back of your PC.
- Connect the USB upstream cable to the monitor and PC.
To learn more about connecting your monitor to the PC, refer to the Dell knowledge-base article How do I connect a monitor to a PC?
CAUTION: Dell P2421D setup must comply to the recommended panel orientation and working angle only. Setting up the monitor in an orientation that is not recommended may damage the monitor and or cause a safety hazard.
When setting up your Dell P2421D monitor, ensure that the monitor front panel buttons is on the bottom right.
Using the Tilt, Swivel, and Vertical Extension
NOTE: This is applicable for a monitor with a stand. When any other stand is bought, please refer to the respective stand setup guide for setup instructions.
With the stand that is attached to the monitor, you can tilt and swivel the monitor for the most comfortable viewing angle.
Figure 1: Using Tilt and Swivel on Dell P2421D monitor
When mounted on the wall or on a monitor arm, the set-up must comply to the recommended panel orientation and working angle.
Figure 2: Orientation of Dell P2421D monitor
Figure 3: Illustration of Dell dual monitor setup
When mounted on the wall or on a monitor arm, the set-up must comply to the recommended panel orientation and working angle.
Use the buttons at the bottom of the monitor to access the On-Screen Display (OSD) menu of the monitor. To access the On-Screen Display (OSD) menu, press Button 5 (Figure 4) at the bottom of the monitor.
To learn more about how to use the On-Screen Display (OSD) menu, refer to the Operating Your Monitor section in the User's Guide of Dell P2421D monitor.
NOTE: Any changes that you make are automatically saved when you move to another menu item, exit the OSD menu, or wait for the OSD menu to automatically close.
Figure 4: Dell P2421D Front Panel Buttons
| Button | Function | Description |
|---|---|---|
| Button 1 | Shortcut key/Preset Modes | Use this button to choose from a list of preset color modes. |
| Button 2 | Shortcut key/Input Source | Use this button to select between the different video signals that may be connected to your monitor. |
| Button 3 | Menu | Use the MENU button to launch the On-Screen Display (OSD). |
| Button 4 | Exit | Use this button to exit the OSD main menu. |
| Button 5 | Power On/Off button (with LED indicator) | Solid white light indicates that the monitor is On and fully functional. Blinking white light indicates the power save mode. |
Resetting a monitor to factory defaults can help resolve many video or display issues. To reset your Dell P2421D monitor to factory default settings, follow these instructions:
- Press Button 3 (Figure 5) on the monitor to enter the On-Screen Display (OSD) Menu.
- Press Button 1 or Button 2 to highlight Others option in the menu and press Button 3 to select.
- Press Button 1 or Button 2 to highlight Factory Reset option in the menu and press Button 3 to select.
- Press Button 5 to confirm the reset action.
Figure 5: Dell P2421D Front Panel Buttons
If your Dell monitor has a blank or black screen, fuzzy or blurry image, flickering, distorted or any other screen abnormalities, running a diagnostic test helps determine if the Dell monitor is functioning normally. To learn more about diagnostic options on a Dell monitor, refer to the Dell knowledge-base article How do I run diagnostics on a Dell monitor?
It is always essential to isolate the monitor while troubleshooting your computer for the following scenarios:
- No Power - Your computer is not powering ON or showing any signs of power.
- No POST - Your computer is not showing any indication of activity, the screen might be blank and will not display the Dell logo during start-up.
- No Video - You are unable to see any display on the screen, able to hear the windows chime but no display is seen.
Your Dell P2421D Monitor provides a self-test feature check that allows you to check whether the monitor is functioning properly. If the monitor and computer are properly connected but the monitor screen remains dark, run the monitor self-test by performing the following steps:
- Turn off both your computer and the monitor.
- Unplug the video cable from the back of the computer. To ensure proper Self-Test operation, remove the video cables (VGA, DVI, HDMI, or DisplayPort) from the back of the computer.
- Turn on the monitor.
- Turn off your monitor and reconnect the video cable: then turn on both your computer and the monitor.
- If your monitor screen remains blank after you use the previous procedure, check your video card (GPU) and computer, because your monitor is functioning properly.
Your Dell P2421D monitor has a built-in diagnostic tool that helps to determine if the screen abnormality you are experiencing is a problem with the monitor or with the video card on your computer.
When you notice screen abnormalities like distortion, clarity, horizontal or vertical lines, color fade , it is always a good practice to isolate the monitor by running the Built-In Diagnostics.
- Make sure that the screen is clean (no dust particles on the surface of the screen).
- Unplug the video cables from the back of the computer or the monitor. The monitor will now enter self-test mode.
- On the front panel, press and hold Button 2 on the front panel for 5 seconds. A gray screen appears.
- Carefully inspect the screen for abnormalities.
- Press Button 2 on the front panel again. The color of the screen changes to red.
- Inspect the display for any abnormalities.
- Repeat step 5 and step 6 to inspect the display in green, blue, black, white, and text screens.
- The test is complete when the white screen appears.
- Press Button 2 to exit the Built-In Self-Test diagnostics.
NOTE: If you do not detect any screen abnormalities upon using the built-in diagnostic tool, the monitor is functioning properly. Check the video card (GPU) and the computer.
If you notice any abnormalities during Built-In Diagnostics, you may get the monitor repaired or replaced if it is under warranty by contacting Dell Technical Support.
If you notice any abnormalities during Built-In Diagnostics, you may get the monitor repaired or replaced if it is under warranty by contacting Dell Technical Support.
During the LCD Monitor manufacturing process, it is not uncommon for one or more pixels to become fixed in an unchanging state which are hard to see and do not affect the display quality or usability. For more information, refer to the Dell knowledge-base article Dell LCD Monitor Pixel Guidelines.
This section provides information about troubleshooting steps that can help resolve the most common issues with the Dell P2421D monitor. Alternatively, to learn more about troubleshooting common issues on Dell monitors, refer to the Dell knowledge-base article Troubleshooting Display or Video Issues on a Dell Monitor.
| Common Problem | What User Experiences | Possible Solution |
|---|---|---|
| No Video - Power LED Off | No picture |
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| No Video - Power LED On | No picture or no brightness. |
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| Poor Focus | Picture is fuzzy, blurry, or ghosting. |
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| Shaky orJittery Video | Wavy picture or fine movement. |
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| Missing Pixels | LCD screen has spots. |
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| Stuck-On or Off Pixels | LCD screen has bright spot. |
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| Brightness Problems | Picture too dim or too bright. |
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| Geometric Distortion | Screen not centered correctly. |
NOTE: When using DisplayPort input, the positioning adjustments are not available.
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| Horizontal or Vertical Lines | Screen has one or more lines. |
NOTE: When using DisplayPort input, the positioning adjustments are not available.
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| Synchronization Problems | Screen is scrambled or appears torn. |
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| Safety-Related Issues | Visible signs of smoke or sparks. |
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| Intermittent Problems | Monitor malfunctions on and off. |
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| Missing Color | Picture does not have color. |
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| Wrong Color | Picture color is not good. |
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| Image Retention from a Static Image Left on the Monitor for a Long Period | Faint shadow from the static image appears on the screen. |
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| Screen image is too small. | Image is centered on screen, but does not fill entire viewing area. |
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| Image Ghosting | Fast moving images leave a trail of shadow images. |
On certain video and applications with fast moving images, imaging ghosting, which appears as a trailing shadow, may occur. Change the Response Time to Fast in the Display menu. |
| No Input Signal when user controls are pressed. | No picture, the power LED light is white. |
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| The picture does not fill the entire screen. | The picture cannot fill the height or width of the screen. |
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| When changing the monitor’s resolution from Windows Display Settings, the image quality may not be good. | Windows Display Settings and the resolution settings on the laptop's video or graphics utility may not be compatible. | Change the resolution using the video or graphics card (GPU) utility like Intel HD Graphics Control Panel. |
| No video when the monitor is connected to a Dell docking station. | The monitor may not receive video signals from the PC when connected to a Dell docking station. | To learn more about how to set-up and configure the Dell P2421D monitor with a Dell docking station, refer to the Dell knowledge-base article Dell P2421D - System Requirements and Supported Configuration. |
| Light leak from the monitor | The monitor appears to have light leak from the edges in a dark room | This is normal behavior of the monitor. Dell consumer monitors are inspected at 150-lux ambient lighting (similar to typical office lighting). |
| Monitor will not display Blu-Ray video after the monitor is powered-off and powered on. | If the monitor is powered-off and powered-on when displaying the Blu-Ray video, the Blu-ray player may lose the data signal from the system to the monitor. |
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| Troubleshooting USB Issues | ||
|---|---|---|
| Specific Symptoms | What User Experiences | Possible Solution |
| USB interface is not working. | USB peripherals are not working. |
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| High-Speed USB 3.0 interface is slow. | High-Speed USB 3.0 peripherals working slowly or not working at all |
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| Wireless USB peripherals stop working when a USB 3.0 device is plugged in. | Wireless USB peripherals responding slowly or only working as the distance between itself and its receiver decreases. |
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| Monitor does not wake up via the USB keyboard or mouse that is connected to the monitor. | In sleep mode, the monitor does not receive power to the USB 3.0 ports. | Wake up the laptop PC using the built-in keyboard or touchpad |
To learn more about how to view or download the User Guides and Manuals for your Dell product, refer to the Dell knowledge-base article Manuals and Documentation for your Dell Product.
- Dell P2421D – User’s Guide
- Dell P2421D – Quick Setup Guide
- Dell P2421D – Dell Display Manager User’s Guide
Frequently asked questions
Using Windows Display Settings
In Windows 10, Windows 8 or 8.1 and Windows 7:
- For Windows 8 and Windows 8.1 only, select the Desktop tile to switch to classic desktop view.
- Right-click on the desktop and click Screen Resolution.
- Click the dropdown list of the Screen Resolution and select 2560 x 1440.
- Click OK
Using NVIDIA Control Panel
To change the resolution using the NVIDIA Control Panel:
- Right-click on the desktop and click NVIDIA Control Panel.
- Click the + symbol next to Display on the left pane.
- Select Change Resolution under Display.
- In the dropdown menu on the right pane, select the resolution 2560 x 1440.
- Click Apply.
Using AMD Catalyst Control Center
To change the resolution using the AMD Catalyst Control Center:
- Right-click on the desktop and click AMD Catalyst Control Center.
- Click the + symbol next to Display on the left pane.
- Select Change Resolution under Display.
- In the dropdown menu on the right pane, select the resolution 2560 x 1440.
- Click Apply.
NOTE: If you do not see the recommended resolution as an option, you may need to update the video card (GPU) driver by visiting the Dell Drivers & Downloads website or the video card (GPU) manufacturers website. To learn how to download and update a device driver, refer to the Dell knowledge-base article How do I download and install a device driver?
To reset the Dell P2421D Monitor to factory defaults, refer to the Reset to Factory Settings section of this article.
The Dell P2421D monitor has two built-in diagnostics that are available:
- Self-Test Feature Check - The self-test feature check on the Dell P2421D monitor allows you to check whether the monitor is functioning properly.
- Built-In Self-Test - The Dell P2421D monitor has a built-in self-test that helps you identify if the screen abnormality is with the monitor or the video card (GPU) on your computer. When you notice screen abnormalities like distortion, clarity, horizontal or vertical lines, color fade , it is always a good practice to isolate the monitor by running the Built-In Diagnostics.
To learn how to run a diagnostic test, refer to the Running Diagnostics on Dell P2421D Monitor section of this Dell knowledge-base article.
The Troubleshooting section of this Dell knowledge-base article provides information about troubleshooting common issues with the Dell P2421D monitor. The section has troubleshooting steps on how to resolve power issues, video issues, color or clarity issues, distortion issues, horizontal or vertical lines, brightness issues or pixel issues and so forth.
To navigate the On-Screen Display (OSD) menu, use the buttons on the monitor. The monitor control buttons are usually on the right side, either on the side, front, or bottom of the monitor. To access the On-Screen Display (OSD) menu, press Button 3 on the monitor.
For more information about using the On-Screen Display (OSD) menu and different menu options, refer to the Operating Your Monitor section in the User's Guide of your Dell P2421D monitor.
Additional monitor information like the model number, firmware version and Service Tag can be accessed from the monitor's OSD (On-Screen Display).
- Press Button 3 (Figure 5) on the monitor to enter the On-Screen Display (OSD) Menu.
- Press Button 1 or Button 2 to highlight Others option in the menu and press Button 3 to select.
- Press Button 1 or Button 2 to highlight Model Number or Firmware Version option in the menu and press Button 3 to select.
- Press Button 4 to exit the OSD menu.
Dell P2421D monitor orientation must be in landscape mode always. This includes any wall-mounted monitors and monitors on a stand. In a multiple monitor setup, Dell P2421D should not be rotated either to 180° (landscape) or 90° (portrait).
CAUTION: Dell P2421D setup must comply to the recommended panel orientation and working angle only. Setting up the monitor in an orientation that is not recommended may cause.
When setting up your Dell P2421D monitor, ensure that the monitor front panel buttons is on the bottom right.
Using the Tilt, Swivel, and Vertical Extension
NOTE: This is applicable for a monitor with a stand. When any other stand is bought, please refer to the respective stand setup guide for set-up instructions.
With the stand that is attached to the monitor, you can tilt and swivel the monitor for the most comfortable viewing angle.
Figure 1: Using Tilt and Swivel on Dell P2421D monitor
When mounted on the wall or on a monitor arm, the set-up must comply to the recommended panel orientation and working angle.
Figure 2: Orientation of Dell P2421D
When you experience a situation where the speakers on your notebook stop working after connecting the monitor to your notebook, refer to the Dell knowledge-base article "Common Troubleshooting Guide for Internal (built-in) Speakers on Dell Laptop PC."
Affected Products
Dell P2421DArticle Properties
Article Number: 000124358
Article Type: Solution
Last Modified: 04 Jun 2025
Version: 6
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