The Xiaomi Mi 9T, known in some regions as the Redmi K20, has long been a mid-range benchmark for its bezel-less design and outgoing camera. However, mechanical damage such as broken glass or stains on the matrix can negate all the benefits of the device. Self-replacement of the display is a complex but feasible process that saves a significant amount of money compared to the services of a service center. It is important to understand that the work requires accuracy, since the phone body is made of glass and metal, and the internal components are very dense.
Before starting to disassemble, you need to evaluate the front of the work. In modern smartphones, the display module is often a single unit consisting of a matrix (AMOLED In this case, and touchscreen, combined with or without a frame, the quality of the components is crucial: the use of the original OLED-The screen will retain color reproduction and energy efficiency, while cheap IPS-If you're doing this, you can make a good lighting workspace and be patient.
In this article, we will discuss the replacement process in detail, paying special attention to the nuances of working with adhesive base and plumes. Replacing the display with the Xiaomi Mi 9T requires mandatory heating of the edges of the case to 80-90 degrees, since the factory adhesive is very durable.
Tools and workplace preparation required
The success of the operation depends on the quality of preparation. You will need a specialized set of tools, because ordinary household appliances can damage delicate components. The main tool will be a thermophen or a heating pad for screens that will soften the adhesive layer around the perimeter of the case. The use of open fire or kitchen stove is strictly prohibited, as this can lead to overheating of the battery and its bloating.
Small screws and plastics will require suction cups, mediators (plastic blades) and a set of screwdrivers that includes cross (usually PH000) and triangular bits. It is also highly desirable to have tweezers with curved ends and isopropyl alcohol to remove glue residue. Don't forget the multimeter if you plan to check the power chains, although this is rarely required for a simple screen replacement.
⚠️ Warning: Before starting any work, be sure to turn off the smartphone. Attempting to turn off the plumes under voltage can lead to a short circuit and failure of the power controller on the motherboard.
Arrange the space so that all parts are at hand. Use a magnetic mat or containers with cells to sort screws, as the Xiaomi Mi 9T uses screws of different lengths, and their entanglement can lead to damage to the thread or breakdown of components. It is also recommended to prepare the adhesive B-7000 or T-7000 for final assembly, as factory adhesive tapes often become unusable at opening.
☑️ Preparation for repairs
Dismantling of the back cover and protective elements
The process of dismantling Xiaomi Mi 9T begins with the removal of the rear glass panel. This is one of the most risky steps, as the glass easily cracks when uneven heating or excessive mechanical impact. Carefully warm the perimeter of the rear cover for 3-5 minutes, constantly monitoring the temperature so as not to overheat the internal components. After warming up, use a suction cup to create a small gap, and carefully insert the mediator.
Move the mediator along the perimeter, gradually cutting through the adhesive layer. Don't try to remove the lid with a jerk - the adhesive should lend itself smoothly. Pay special attention to the areas around the main camera module and the fingerprint scanner if it is located in the rear (although in Mi, the image is not a good one). 9T The scanner is hidden in the screen, but there may be additional attachments in the camera area. NFC-antennae and main board.
The next step is to remove the plastic safety panel that covers the battery and the bottom of the smartphone, which is also glued, but it holds weaker than the back cover, carefully unscrew all the visible screws that hold this panel, and remove it, gaining access to the battery and the plumes, and there is a connector for connecting the charger and speaker.
- 🔥 Warm up the body evenly, avoiding spot overheating in one zone for more than 10 seconds.
- 🛠️ Use only plastic tools to snap latches, metal can damage insulation.
- 🔋 Be careful with the battery: do not pierce it or bend it.
Once the protection is removed, check the insides for battery bloating, and if the battery is defective, it is better to replace it immediately while the phone is disassembled, which will ensure safety and avoid re-disassembly in the future, and now that the insides are open, you can switch to disconnecting the power and removing the motherboard.
Nuances of work with NFC-antenna
Disconnecting the battery and removing the motherboard
The first step after accessing the insides is to turn off the battery, find the battery plume that goes to the motherboard, and gently disconnect the connector with a plastic blade, which is a critical step to ensure electrical safety during further manipulation. Even after disconnection, the capacitors can still have a charge, so avoid touching the contacts with metal objects.
To remove the motherboard, you need to unscrew all the screws that lock it and metal shielding plates. In Xiaomi Mi 9T, the board sits quite tightly in the case. Before raising the board, make sure that all the plumes are turned off: the main display plume, the touchscreen plume, the lower board plume (with a microphone and charging) and the side button plume.
⚠️ Warning: The plumes in modern smartphones are very thin and fragile. When they are turned off, pull strictly for the connector, not for the plume itself, otherwise there is a risk of breaking the current tracks.
Carefully remove the motherboard by slightly lifting it first on one side, then on the other. Pay attention to the location of the vibrator and the front camera, which can interfere with the extraction. Put the board in a safe place, preferably on an antistatic mat. Now the case of the smartphone is practically empty, and you can start working with the display module.
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Take a picture of all the screws before you unscrew them. In complex devices like the Mi 9T, the screws can vary in length even within the same group, and an assembly error can cause damage to the board.
Replacement of the display module: step-by-step instructions
Now the most critical thing is to replace the screen itself, and unlike the older models, it's held on a powerful adhesive layer all around the perimeter, and use the thermophene again to warm up the front of the smartphone, and be very careful that overheating can damage the new matrix, if it's already installed, or deform the frame.
Using a suction cup and mediators, carefully (separate) the old display from the frame. Move slowly, helping the process with isopropyl alcohol, which can be slightly poured into the gap to dissolve the glue. After removing the old module, carefully clean the frame of the glue residues using a plastic card or blade (with caution) so that the new part sits perfectly smoothly.
Install a new display module. Before you finally stick, test the connection: connect the plumes to the motherboard (which you can not install completely, but just plug in the plumes) and turn on the phone. Check the touchscreen, the presence of broken pixels and the proximity sensor. If everything works, turn off the phone, apply a new glue B-7000 on the frame and tightly press the display.
For even distribution of glue and fixation, use special clamps or tightly wrap the phone with rubber harnesses for 1-2 hours. Make sure that the screen does not get air and the glue does not leak onto the matrix. After drying the glue, you can start the reverse assembly of the device in the order, reverse disassembly.
Comparison of original and copy displays
When choosing a spare part for Xiaomi Mi 9T, the user faces a variety of options, and it is important to understand the difference between them.The original guarantees compliance with all the declared characteristics, including brightness, color reproduction and fingerprint scanner.
Below is a table to help you compare the main characteristics of the different types of displays available on the market:
| Characteristics | Original (OLED) | Quality copy (OLED) | Cheap copy (IPS) |
|---|---|---|---|
| Type of matrix | AMOLED | AMOLED (often a rigid substrate) | IPS LCD |
| Fingerprint scanner | It works perfectly. | It works, but it can be slower. | Does not work or is not operating smoothly |
| Thickness of the frame | Standard (thin) | A little thicker than the original. | Noticeably thicker ("chin") |
| Brightness | Up to 800 nits (HBM) | Up to 500-600 nits | Up to 400 nits |
| Energy consumption | Low. | Average. | High. |
As you can see from the table, the installation IPS-matrix AMOLED — It's a compromise that only comes on a budget, and you lose color saturation, you lose black depth, and, most of all, you can run into a broken fingerprint scanner that you can find in Mi. 9T The original display is always preferred, even if it costs more.
In addition, cheap copies often have problems calibrating the touchscreen, leading to "phantom" pressing or ignoring touches at the edges.When buying, be sure to check the packaging: original Xiaomi parts often come in sealed packages with holograms and other products. QR-authentication codes on the official website.
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Savings on display for AMOLED-Smartphone with a subscreen scanner almost always leads to loss of functionality and reduced image quality.
Smartphone Assembly and Primary Diagnostics
Once the new screen is firmly glued and dried, start building. Set the motherboard, gently stacking all the plumes in their seats. Make sure the display plume snaps to a characteristic click. Tighten all the screws to their length and location. Put back the metal protection and the plastic battery panel.
Before you stick the back cover, turn on your phone again and run a final diagnostic. Check the speakers, microphone, vibration response and, of course, sensor. Pay special attention to the outgoing front camera — make sure that the mechanism does not jam and works correctly through the software menu.
⚠️ Warning: If the phone doesn't turn on after assembly, don't panic. Check the battery plume and main plume connection. Often the problem is with an incomplete connector.
If all tests are successful, apply a new layer of glue to the perimeter of the back cover and press it against the body. Use harnesses to fix for a few hours. Once the glue is fully assembled and dryed, the smartphone is ready for active use. Properly executed repairs will extend the life of your Xiaomi Mi 9T for several more years.