Buying a new TV is always exciting, especially when it comes to high-quality equipment from Xiaomi. However, even premium brands have a manufacturing defect that may not be noticeable in the exhibition hall, but will become apparent on the big screen in your living room.
Many users mistakenly believe that the matrix defects are visible immediately and ignore the initial diagnosis. In fact, to detect a broken pixel, you need to create specific lighting conditions and display special test images. Ignoring this stage can lead to the fact that you will find the defect only after the return of the product to the store expires.
In this article, we will discuss how to make a professional screen diagnosis of your Mi TV or Redmi TV without using complex equipment. You will learn how the types of defects differ, what tools are best for Android TV and how to proceed correctly if a problem is found. The warranty period for returning goods with factory defects is often limited to 14 days, so checking on the day of purchase or delivery is critical.
Types of Matrix Defects and Their Differences
Before you start checking, it's important to understand that not every dot on the screen is a fault that requires changing the panel. There are several types of anomalies that may look similar visually, but have different origins, and understanding these differences will help you communicate with the service center in a reasoned manner.
The most common are stuck pixels, which are subpixels that are constantly lit in the same color, red, green or blue, and unlike completely broken elements, they respond to image change and are often software-recoverable, and are easily seen against a dark background where they appear as bright, colored sparkles.
Dead pixels are dots that don't glow at all. They look like black dips on a light background. It's almost impossible to reconstruct them using software methods, because it's physical damage or a burnt transistor. There are also hot pixels that glow white regardless of the image being displayed, which is especially noticeable in black frames.
- 🔴 Stuck pixel: burns in one color (RGB), visible on a black background, often treated.
- ⚫ Broken pixel: always black, unresponsive to signal, visible on white background.
- ⚪ Hot pixel: glows white, visible in dark image.
- 🌫️ Lights: Uneven lighting areas are not pixelated marriages.
And I also have to mention the lights, which are often confused with broken pixels, which are areas of the matrix's uneven glow that are only visible on dark scenes, and unlike point defects, the lights are space-based and are a feature of IPS technology, not a defect in the strict sense of the word, if they do not exceed the manufacturer's acceptable standards.
Preparation of equipment and conditions for the test
The quality of the test depends on the conditions in which it is performed. Incorrect lighting or poor quality of the initial signal can hide defects or, conversely, create the illusion of marriage where there is none. First, make sure that the TV is connected to the source of the signal with the maximum resolution supported by the model.
If you are using built-in Smart apps TV, Make sure the internet connection is stable, as streaming a low-quality test video can mask the broken pixels with compression artifacts. USB-It's also important to wipe the screen with a soft microfiber so that the dust isn't mistaken for a matrix defect.
⚠️ Warning: Do not diagnose when bright sunlight falls directly on the screen, glare and reflections will make it impossible to detect black broken pixels and distort the perception of color reproduction.
For maximum efficiency, the best way to adjust the image is to reset to factory or to switch to "Cinema" or "Standard" mode, turning off all dynamic color enhancements and noise reduction. Aggressive image processing algorithms in "Bright" or "Sport" mode can smooth out single pixels, hiding the problem.
☑️ Preparation for matrix verification
Use of built-in tests and applications
The Android TV operating system that powers Xiaomi TVs provides a lot of diagnostics, and the easiest way to do this is to use the built-in features or install a dedicated app from the Google Play Store, eliminating the need to search for files on your computer and toss them onto a flash drive.
One of the most popular and reliable tools is the Screen Test app or its counterparts, such as the Dead Pixel Test. Once installed, launch the program and select the full-screen color display mode. The application will consistently change the colors of the screen, allowing you to carefully examine the entire surface of the matrix.
The screen settings menu may also include a diagnostics section, and the path to it is usually: Settings → Device → About TV → Diagnostics (the location may vary depending on the version of PatchWall firmware or pure Android), where you can run an automatic test that will check not only the pixels, but also the sound system and ports.
- 📺 Screen Test: a classic application with a set of monochrome screens.
- 🎨 Dead Pixel Buddy: a handy tool with zoom and a choice of colors.
- 🛠️ Pattern Test: Built-in feature in the engineering menu (for advanced ones).
- 📹 YouTube 4K: use of special test rollers in high resolution.
If you don't want to install unnecessary apps, you can use online services through the built-in browser, if you have one in your model. However, browsers on TVs often run slowly and may not support the correct display of colors in the full range, so native apps are preferable.
Secret Engineering Menu
Check through USB-storage
The most accurate result is checked with the help of pre-prepared images stored on the USB-This method eliminates the impact of the quality of the Internet connection and compression of the video stream. You'll need a computer to create or download a set of test images in resolution. 3840×2160 (for 4K televisions) or 1920×1080 (full HD).
Create a folder on a flash drive and put 6 images in it: all black, white, red, green, blue and gray. PNG or JPG High quality, no compression artifacts. USB-port of the TV, open the built-in media player and start viewing images in slideshow mode.
| Color of dough | What reveals | What to look at |
|---|---|---|
| Black. | Stuck (color) pixels | RGB bright spots |
| White | Broken (black) pixels | Dark flops |
| Red/Green/Blue | Defects of subpixels | Points of different color |
| Gray (50%) | Unevenness of illumination | Spots and clouds |
When viewing each color, slowly approach the screen and examine it from different angles. Pay special attention to the edges of the matrix and angles, as there are more defects due to pressure during assembly or transportation. If you find a suspicious point, switch the background color to help you understand whether a broken pixel or just a speck of dust.
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Use your smartphone flashlight at a sharp angle on the screen (almost parallel to the surface) to better see black batted pixels on a white background.
Analysis of results through YouTube and online services
If you don't have a flash drive, YouTube will be a great helper. On Xiaomi or specialized technical channels, you can find videos called "Pixel Test 4K" or "Dead Pixel Test." Run such a video in the highest quality (make sure you choose 2160p or 4K, not "Auto").
The advantage of this method is that the video lasts a few minutes and automatically changes colors, you just have to watch, but there is a disadvantage: compression of YouTube video stream can "blur" single pixels, especially if the Internet connection is unstable, so this method is better used as a preliminary or additional.
There are also specialized sites such as jscreenfix.com that have mobile and mobile-friendly websites. TV-And when you open a website like this, you have access to a noise generator and color fields, and it's convenient, but it requires a working browser and a remote that can input text for the site address.
What to do if defects are found
If you find one or more broken pixels during the inspection, do not immediately panic. Matrix manufacturers, including Xiaomi partners (for example, CSOT or BOE), allow the presence of a certain number of defective points in accordance with the ISO 13406-2 standard. Usually, a warranty exchange is subject to goods with a defective class above the permissible (for example, more than 3-5 bit pixels in one zone).
So the first step is to try software recovery. There are videos that change colors quickly at high frequency, which can "curl" a stuck subpixel. 10-15 If the dot is gone, you're lucky, it was a temporary failure. If not, go to the documentation.
Take clear photos of the defect with different background colors. It is important that the photo shows that the dot does not change. Keep the check and the package. If the number of defects exceeds the rate specified in your sales contract or consumer law, you have every right to demand a replacement TV or a refund.
⚠️ Warning: The store may require independent examination. Do not attempt to "treat" the screen with a mechanical action (pressing a finger), as this will lead to cracks and loss of warranty.
If the store fails, refer to the law. For TVs with a diagonal of more than 40 inches, the permissible number of broken pixels may be higher than for monitors, so carefully study the technical documentation of your Mi TV model.
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Having 1-2 bit pixels is often not considered a marriage by international standards, but having a cluster of 3 or more dots in the center of the screen is almost always a reason to replace it.