How to check a screen for dead pixels on Android Samsung

Owners of flagship and budget smartphones Samsung Galaxy often face the need to check the quality of the matrix immediately after purchase or during operation. Even expensive OLED screens can develop defects that, over time, lead to burnout or complete failure of part of the image. Timely diagnostics help to avoid warranty problems and save money.

In this guide we will look at all the available methods: from built-in engineering codes to using third-party applications. You will learn to distinguish real dead pixels from ordinary dust under glass and understand when to take the device to a service center.

The verification procedure takes no more than 5-10 minutes, but requires a certain sequence of actions. You should not ignore small spots, since on AMOLED matrices they can be a sign of incipient burnout of organic LEDs.

What are dead pixels and how do they look on AMOLED

Unlike old IPS matrices, where a pixel consists of three subpixels (red, green, blue), technology Super AMOLED from Samsung works differently. Here, each pixel glows independently. The defect can appear as a constantly burning point of one color or, conversely, as a black hole that does not respond to changes in the image.

Most often, users notice three types of faults. The first type is a “stuck” pixel, which lights up in one color (red, green or blue) on any background. The second type is a dead pixel, which is always black and does not light up. The third type is specific to OLED - burn-in, where an area of ​​the screen loses brightness and leaves a ghost image.

It is important to understand that a single defect may be an acceptable manufacturing defect according to some manufacturers' standards, but for the consumer it is a significant disadvantage. If you discover display anomaly in the first days after purchase, you have every right to replace the device.

⚠️ Attention: Do not confuse dead pixels with dust trapped between the protective glass and the matrix. Dust usually looks like a gray spot with jagged edges and is visible only on a light background, while a pixel has a clear geometric shape.

Using the Samsung engineering menu for diagnostics

The most reliable and fastest way to check the screen without installing unnecessary apps is to use the secret engineering menu. It is built into the firmware of all smartphones Galaxy S, Galaxy A and other series. This method allows you to run a built-in hardware test.

You do not need root access to access diagnostics. Just open the standard Phone application (dialer) and enter a special combination of characters. The system will automatically redirect you to a hidden settings section intended for service engineers.

Enter the following code in the dialing field:

#0#

After entering the last asterisk, the screen should instantly switch to testing mode. You will see a grid with buttons, each of which is responsible for checking a specific component: speaker, sensor, vibration and, of course, the display.

In the menu that opens, find buttons with color names: Red, Green, Blue, Black, White. By clicking on them, you paint the entire screen in monochrome. This is an ideal way to identify any deviations in the operation of the matrix.

Step-by-step guide for visual inspection

After entering the engineering menu or running a color test, you need to carefully inspect the surface of the display. It is best to carry out this procedure in good lighting, but without direct glare on the screen, which can hide defects.

Start testing with white. Black (dead) pixels and burn-in spots are best seen on a white background. Then switch to primary colors. Red, green and blue modes will help you find stuck subpixels that may glow in the wrong shade.

Pay special attention to the edges of the screen and the area around the cutout for the camera. In these areas, the matrix experiences the greatest stress during assembly, so the risk of defects appearing there is higher. If you notice a point that does not change color when switching modes, this is a sure sign of a breakdown.

For accurate diagnosis, it is recommended to repeat the color switching cycle 2-3 times. Sometimes a stuck pixel can “come to life” after several cycles of turning on and off, but if it remains unchanged, the problem is hardware.

What to do if the pixel blinks?

If the dot periodically changes color or goes out, this may indicate an unstable contact of the matrix cable or a problem with the power controller. In this case, the device requires professional repair, as the defect will progress.

Third-party applications for in-depth analysis

If the built-in menu is unavailable for some reason or you want to conduct a more detailed analysis using special algorithms, you should contact the store Google Play. There are many free utilities created specifically for testing displays.

One ​​of the most popular solutions is the application Dead Pixel Test or Screen Test. These apps don't just show colors, they can also run automated inspection scripts, saving you time. They also allow you to scale the image to search for micro-defects.

Another useful tool is Display Tester. This application provides advanced statistics, including checking for backlight uniformity (relevant for LCD) and glow uniformity (for OLED). It can also calibrate colors, which can be useful after identifying problems.

Application name	Main function	Presence of advertising	Permission requirements
Dead Pixel Test	Monochrome fill	Minimal	No
Screen Test	Checking the sensor and colors	Absent	No
Display Tester	Deep diagnostics	Yes in Pro versions	No
TestM	Full device test	Yes	No

When using third-party software, make sure that the screen brightness is turned up to maximum. A dim glow can hide weak defects that will become noticeable only under high load on the matrix.

Differences between factory defects and mechanical damage

It is important to be able to distinguish the nature of the defect, since the possibility of warranty service depends on this. Manufacturing defects usually appear in the form of perfectly round dots or geometrically correct lines that are visible from the first day.

Mechanical damage, on the contrary, often looks like cracks, stains or areas with impaired color rendering and an irregular shape. If you drop your phone and a stain appears, the service center classifies this as a hit, and not as a defective matrix.

There is also the concept of “permissible number of dead pixels.” According to international ISO standards, the presence of several defective pixels (usually up to 3-5 per million) may not be considered a reason for replacement unless they are grouped in one place. However, the policy Samsung in different regions may differ.

⚠️ Attention: If you find a defect, do not try to “massage” the screen with your finger or press it forcefully. On modern thin OLED panels, this will most likely lead to irreversible damage to the crystals and loss of warranty.

Warranty cases and device return

If the check confirms the presence of dead pixels, the next step should be a visit to an authorized service center. For a successful return or repair, it is extremely important to preserve the presentation of the device and all accessories included in the kit.

When contacting the service, specialists will conduct their own diagnostics using professional equipment. They will check the number of defective points with internal regulations. If the case is recognized as under warranty, you will be offered a replacement of the display module or the entire device.

If you purchase a smartphone in a large chain store, the consumer protection law often allows you to return a product of inadequate quality within 14 days without lengthy examinations, if the defect is obvious. Keep the receipt and box until this period expires.

Remember that application processing times may vary. In some cases, it is necessary to send the device for factory examination, which takes up to 20-30 days. Be prepared for the fact that during this period you will not be given a replacement phone if the product category does not imply this.

Is it possible to restore a stuck pixel programmatically

Sometimes the pixel is not dead, but simply “stuck” in one state. For such cases, there are stimulating apps that quickly switch colors in the problem area with high frequency. This can make the crystal work again.

One ​​method is to use online services or a YouTube video called “Pixel Fixer”. These videos contain shimmering multi-colored squares. You need to place the browser or player window exactly above the defective area and leave it for 10-20 minutes.

The effectiveness of this method is about 50-60% for stuck pixels and almost 0% for dead ones. If after an hour of “massage” with color the dot has not disappeared, most likely the physical structure of the LED is broken and this cannot be corrected programmatically.

⚠️ Attention: Prolonged display of rapidly changing bright colors may cause discomfort in people with photosensitive epilepsy. Use this method with caution and do not look at the screen too closely.

Does protective glass affect the visibility of pixels?

High-quality protective glass does not affect the performance of pixels. However, cheap glass with a poor oleophobic coating or adhesive layer can create optical distortions that visually resemble matrix defects. Before diagnosing, make sure that the screen is clean.

How many dead pixels are acceptable under Samsung's warranty?

Officially, Samsung does not publish strict standards for consumer electronics in open sources, focusing on the ISO 9241-307 standard. Typically, replacement is performed if there are more than 5 dead pixels or if they are grouped into a cluster. However, the decision is always made individually by the service center.

Can dead pixels appear after a software update?

A software update itself cannot physically break a pixel. However, changing display algorithms or color calibration can make previously invisible defects more obvious to the user's eye.

Is it dangerous to use a phone with dead pixels?

This is not dangerous for eye health, but one dead pixel can be a harbinger of the defect spreading. On OLED screens, near the dead point, organic matter may begin to degrade over time, increasing the black spot.

How to distinguish burn-in from a dead pixel?

Burn-in looks like a dull spot or shadow from interface elements (status bar, keyboard), which is visible on a plain background. A dead pixel is a clear dot that either glows with a bright color or is completely black, regardless of the content on the screen.