How to check the screen of Xiaomi phone for performance: a complete guide with tests

Xiaomi's smartphone screen is not just a display, but a key element that accounts for 90% of the user experience. Cracks, broken pixels, broken sensor zones or color rendering problems can turn even a flagship model into a useless piece of plastic. But how do you know that the screen is really faulty, and not to blame a software bug or temporary glitch?

In this article, we will discuss 7 professional screen screen testing methods on Xiaomi smartphones (including Redmi, POCO and Black Shark models), learn how to identify hidden defects that are not visible during normal use, but can manifest themselves after a month of use, and what tests you need to do before buying a used phone to avoid running into a “cat in a bag”.

1. Visual inspection: what can be seen with the naked eye

Start with a basic check that doesn't require special tools. Take your phone and look carefully at the screen in good light (better under direct sunlight or a bright lamp).

• 🔍 Cracks and chips—even microcracks can disperse over time and cause the display to fail completely.
• 🎨 Spots and stains – often appear after moisture is ingested under glass or when polarizing film is detached.
• 🖥️ Uneven backlighting – yellow or gray areas may appear on a black background (e.g., when off).
• 🔄 Repair marks – if the screen has already been changed, check if there are gaps between the glass and the case, if the edges of the glue stick out.

Pay special attention to the corners of the screen, which are the most vulnerable places when you fall, and if you notice rainbow stains, it's a sign of damage to the matrix, which is not fixed by software and requires a replacement of the display.

⚠️ Warning: Don't confuse mechanical damage with OLED- burnout! AMOLED- screens (installed in Xiaomi 12/13/14, Redmi K50, etc.) may have ghost images from static interface elements after long use, not a defect, but a feature of the technology.

2.Broken pixel test: how to find "dead" points

Broken pixels are constantly burning or inactive dots on the screen, and they can be due to factory defects, physical stress or overheating. To identify them, use one of the methods:

Method 1: Built-in diagnostics menu (for new models)

Most Xiaomi smartphones after 2020 have a hidden test menu.

1. Open the Phone app.
2. Enter the combination: ##6484## (for some models, #4636##).
3. Choose Display Test or Touch Test.

The system will consistently display monochromatic screensavers (red, green, blue, black, white) and at each stage, look closely at the screen, and the broken pixels will be distinguished by contrasting color.

Method 2: Third-party applications

If there is no built-in test, install one of the verified applications:

• 📱 Screen Test (a simple interface that supports all Xiaomi models)
• 🔍 Dead Pixel Detect and Fix (allows you to not only find, but also try to "reanimate" pixels).
• 🎯 Display Tester (Extended Tests for OLED- Screens)

Important: Check reviews before installing – some testers may contain ads or collect data. We recommend downloading apps only from the official Google Play.

Set the brightness of the screen to 100%|Close all background applications|Check the screen in a dark room.|Use a magnifier for an accurate inspection-->

3. Touch layer check: Does the screen respond to touch

A faulty sensor is one of the most common problems after falling or getting moisture, to check its performance:

Method 1: Built-in test (for MIUI)

On Xiaomi smartphones with MIUI 12+ firmware, there is a hidden sensor diagnostic function:

1. Go to Settings. → The phone.
2. Click 5 times in a row on the MIUI version (you will be notified "You became a developer").
3. Return to the main settings menu, open Additional → for developers.
4. Activate the Sensor Debugging Mode.

Then you'll have colored dots on the screen that visualize your touches, and then you'll have your finger swipe all over the display, and if some of the areas don't show the dots, the sensor doesn't work there.

Method 2: Online services

If there is no built-in test, use web applications:

• 🌐 Touch Screen Test draws a trace of your finger.
• 🖥️ Display Tests is a comprehensive sensor and matrix test.

Note multi-touch: On modern Xiaomi, the screen must recognize up to 10 simultaneous touches, and you can check this in a game or a special test (for example, MultiTouch Tester in the Play Market).

⚠️ Warning: If the sensor is delayed (especially in cold weather), the problem may be in the display controller, not the glass itself, and only repairs at the service center will help.

4. Color reproduction and contrast test

Color reproduction problems often go unnoticed, but they can be a huge loss of experience, such as a lost white balance that can cause eye fatigue and low contrast can cause poor visibility in the sun.

To verify:

1. Open any image with a gray gradient (you can find Google for the "gray gradient test").
2. See if there are bandings on the screen – this is a sign of a low-quality matrix or driver problems.
3. Compare colors to another device (like a PC monitor) and notice the shades of skin, greens, and palate that should look natural.

If you notice any deviations, try resetting the screen to factory settings: Settings → Display → Additional → Reset colors. If this does not help, the problem may be a damaged plume or a faulty matrix.

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For accurate color calibration, use Screen Balance (available on the Play Market) to adjust the gamut, temperature and saturation separately for each color channel.

5. Checking the illumination and uniformity of the illumination

Uneven backlighting (called the cloud effect) is most common on IPS- screens, manifesting as light or dark spots on a uniform background, to detect defects:

1. Set the brightness to 50-70%.
2. Open any monochromatic image (preferably gray or white).
3. Look at the screen at an angle of 30-45 degrees.

If you notice yellow sliding around the edges (especially in the lower part), this is a sign of detachment of the LED backlight, a defect that often appears after overheating or impacts. AMOLED- screens instead of "clouds" can show gradient dimming at the edges, which is normal for the technologies of the Samsung E4/E5 used in the Xiaomi 12 Pro or Redmi K60.

For more accurate diagnosis, use YouTube test videos (search for "Xiaomi backlight bleed test"). Videos with rapidly changing colors will help to identify even mild manifestations of the defect.

Phantom touch and spontaneous pressing test

Ghost touches are when the screen responds to a press that was not there, and most often the problem is:

• 👻 When charging the phone.
• 🌡️ In cold or hot weather.
• 💧 After moisture is injected.

To check:

1. Put your phone on the table and don’t touch the screen for 1-2 minutes.
2. Open Settings → Applications → Latest and see if random apps appear there.
3. Run the keyboard (for example, in notes) and see if the characters are entered by themselves.

If ghosts appear, the reasons may be as follows:

• 🔌 Problems with plume (often after falls)
• 🔋 Faulty charging controller (if the glitch is only when connected to the network).
• 💧 Oxidation of contacts (after moisture is ingested).

⚠️ Warning: If the phone vibrates for no reason at the same time as the "ghost" touch, it's a sign of a short circuit in the touch layer.

7. Checking the screen after falling or getting moisture

If the phone falls or comes into contact with water, the screen needs to be checked very carefully, and even if it looks normal, internal damage can occur later.

1. Turn off the phone and inspect the case for cracks or corrosion.
2. If the screen is turned on but the image is distorted (strips, artifacts), do not try to use it – this can aggravate the damage to the matrix.
3. Check the response to touch in different parts of the screen. After impact, the corners often fail.
4. Connect the phone to a PC. If the computer can't see it, but the screen is working, the problem may be in the damaged USB- port, not the display.

For phones with factory water protection (Xiaomi 13 Ultra, Redmi K60 Pro, etc.) after contact with liquid:

• 🚫 Do not dry with a hair dryer or on a battery - this can warp the screen.
• 💨 Wet the moisture with a napkin and leave the phone in a dry place with ventilation for 24 hours.
• 🔋 Do not turn on the device until you are sure it is completely dry.

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Even if the phone is working normally after a fall, hidden defects may appear within 2-3 weeks (for example, plume detachment or contact corrosion).

FAQ: Frequent questions about screen check Xiaomi