The Xiaomi Mi 9T (also known as the Redmi K20 in the domestic market) is a device that has long been considered the benchmark for framelessness thanks to a front-facing camera. However, like any electronic device, it is not immune to mechanical damage, moisture or natural battery wear. Owners often face the need to replace a broken rear window, a worn battery or a failed display module.
Disassembly of this device requires a certain skill, since the design is devoid of the usual hatch for the battery and assembled on strong layers of glue. Before starting work, you need to understand that a violation of the factory seals can deprive you of an official warranty if it has not expired. It is important to prepare a workplace with good lighting and not to be distracted by extraneous affairs, since small screws are easy to lose, and sloppy movement can damage fragile plumes.
In this article, we will take a closer look at the Mi 9T dismantling process, focusing on safely removing the rear panel and properly disabling the internal components. We will take a look at the nuances of working with adhesive joints and tell you what tools are really needed for quality repairs. Following the instructions will help you avoid common errors and keep the functionality of the device after assembly.
Tools and workplace preparation required
A high-quality disassembly of a smartphone is impossible without a specialized tool. Using improvised tools such as knives or needles significantly increases the risk of damage to the body or internal components. To work with the Xiaomi Mi 9T, you will need a minimal but professional kit that will ensure the safety and efficiency of the process.
First of all, get a heating equipment. It can be a professional heating pad, a thermophene or, in extreme cases, a household tile, but with the latter you need to be extremely careful not to overheat the glass. Too low will not soften the glue, and too high can damage OLED-matrix.
- 🔧 A set of precision screwdrivers (cross Pentalobe and Phillips) for twisting screws of different caliber.
- 🔥 Thermophene or heating platform for softening the adhesive layer under the back cover.
- 💳 Plastic cards, mediators or special blades for uncoupling the body without scratches.
- 🧲 Magnetic mat or organizer for sorting screws, so as not to confuse them when assembling.
Also, don't forget isopropyl alcohol, which is used to clean surfaces of old glue before installing a new lid or battery, and is best done on a clean, non-slippery surface where static electricity is excluded, which can be dangerous to electronic circuit boards.
⚠️ Warning: Before starting any work, be sure to turn off the smartphone. Attempting to disassemble the on device with the battery connected can lead to a short circuit and the motherboard fails.
Preparation takes no more than 10 minutes, but saves hours of nerves during the repair process. Make sure you have dielectric tweezers on hand to work with small plumes. Lack of the right tool often leads to simple glass replacement turning into complex repairs with soldering components.
Removal of the back cover and access to the insides
The most difficult part of dismantling Xiaomi Mi 9T is neat removal of the rear glass panel, which is glued around the perimeter with powerful double-sided tape, start by heating the back of the smartphone, evenly warm the glass for 2-3 minutes, holding the hair dryer at a distance of 3-5 cm or putting the phone on the heating pad.
Once heated, take a suction cup, attach it to the bottom of the back cover and pull it up slightly, creating a gap. Insert a plastic blade or mediator gently into the resulting gap. Do not use metal tools at this stage, as the Mi 9T glass can crack from point pressure.
Move the blade along the perimeter of the body, gradually cutting the adhesive layer. Pay special attention to the corners and areas around the camera module where the adhesive is usually the most. If you feel strong resistance, stop pulling and warm up the problem area again. Sharp movements can lead to chipping or complete destruction of the back panel.
What to do if the glass cracks when removed?
When the lid is fully detached, don't try to open it like a book right away. It's connected to the main board by a thin fingerprint scanner plume (if the model requires it, although there may be button or antenna plumes in the 9T scanner, but you may have a perimeter for connections before putting the lid aside.
Dismantling the protective plate and disconnecting the plumes
When you take the back cover off, you'll see a black shield covering the motherboard and the battery, and it's mounted with a lot of screws of different sizes. Use the appropriate bits to twist them, usually Phillips #00 or #000. It's important to twist the screws sequentially and remember their location.
When you remove the plate, you'll have access to key nodes on your smartphone, and the first thing you need to do is turn off the power, find the battery connector and gently unplug it from the motherboard, putting a plastic blade on the base of the connector, a must before any further manipulation of the display or camera.
- 🔌 Turn off the main display plume, usually located in the upper or central part of the board.
- 📸 Carefully disconnect the main and front (mechanical) camera plumes if they interfere with access.
- 🔊 Remove the plume of the lower board (sub-board) running along the left or right edge of the case.
- 📡 Disable antenna cables if they are laid over components and interfere with board removal.
When working with plumes, be extremely careful: they are very thin and easily break. If the connector has a latch (flag), it must be bent before removing the plume. In the Xiaomi Mi 9T, many connectors have reliable fixation, but excessive force when disconnected can damage the connector itself on the board.
⚠️ Warning: Never pull the plume itself to detach it. Always act only on the hard part of the connector or use a special tool to gently lift it.
Once all communications are turned off, you can unscrew the propellers that hold the motherboard, which are not very many, but they can be hidden under other elements, and then the board is freely removed from the case, opening access to the vibrator, loudspeaker and other elements.
☑️ Pre-assembly check
Replacement of the battery and lower board
The battery in the Mi 9T takes up a significant portion of the interior space and is glued to the frame. It will require heating again to replace it. Warm up the battery area through the screen (if it is removed) or through the internal partitions if the battery is available from the back. In the 9T model, the battery is under the main board, so removing it often requires a complete dismantling of the "filling".
Use special plastic blades or, in extreme cases, a thin line to cut the adhesive layer under the battery. The movements must be sawing, without jerking. It is strictly forbidden to use metal objects to tweak the battery - a puncture of the lithium-ion cell will lead to ignition and chemical burn.
The subboard contains a USB-C charging connector, microphone and speaker, and it's mounted with screws and plastic latches, and when you install a new board, make sure that the contact pads are clean, and often charging problems are solved by replacing the module or cleaning it thoroughly with ultrasound.
| Component | Type of attachment | Difficulty replacing | Risks. |
|---|---|---|---|
| Battery | Adhesive tape | Tall. | Bloating, puncture fire |
| Lower fees | Screws + plume | Medium | The antenna plume break |
| Basic fee | Lots of screws + plumes | Tall. | Damage to connectors |
| Camera mechanism | Screws + plume | Medium | Damage to the engine gears |
When installing a new battery, make sure that its plume is not squeezed. In the Xiaomi Mi 9T, the space is very dense, and any excess bending can lead to a rapid failure of the new battery. After installing a new battery, conduct an initial charge without installing the back cover to make sure that the new battery is working properly.
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To facilitate future battery replacement, stick a double-sided tape strip with "tongues" to pull on the back of the battery, allowing the battery to be removed without heating and risking damage next time.
Work with the display module and frame
The screen in the Mi 9T is fixed around the frame and requires careful separation. If you change the display assembled with the frame, the task is simple: just move all the internal components from the old frame to the new one. If only the glass or matrix changes, the process becomes jewelry.
To remove the display, you need to unscrew all the screws around the perimeter and under the speaker. Then, using the suction cup and the shoulder blades, you need to contour the matrix from the frame. OLED-They're very fragile and sensitive to pressure, and any local pressure can create an ink stain that spreads all over the screen.
When you re-paint the frame, it's important to remove the old glue completely. Use isopropyl alcohol and plastic scraper. The surface should be perfectly smooth and fat-free. Applying a new glue (B-7000 or T-8000) requires precision: the layer should be uniform, without bubbles or excess that can be squeezed out.
The mechanism of the retractable camera deserves special attention. When working with the front of the phone, try not to disturb this assembly unnecessarily. Mechanism, and the introduction of glue or dust can lead to its jamming. If the mechanism still requires maintenance, act extremely carefully so as not to damage the gears or the engine plume.
Assembly of the device and verification of functionality
The Xiaomi Mi 9T is built in reverse order, but requires even more care. Start by installing the motherboard and connecting all the plumes. Make sure each connector is in place before the click. After that, you can temporarily plug the battery and check the device's power on without twisting the screws.
Check the touchscreen, the sound, the vibration, the cameras, and most importantly, the mechanism of the outbound camera. If everything is working correctly, you can proceed to the final fixation. Twisting all the screws in order to keep the order, so that the pressure on the board is evenly distributed.
Before you stick the back cover, degrease the frame and the lid with alcohol. Apply the new adhesive compound with a thin layer around the perimeter. Press the lid and lock the phone with rubber harnesses or a 15-20 minute load to primary polymerize the adhesive. It takes about 2-4 hours to dry completely.
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Quality assembly depends not so much on the strength of the screws clamping, but on the purity of the contacts and the correct position of the plumes. Don't rush to twist everything until you check the operation of the smartphone in assembled, but not glued.
Once the glue is dry, remove the excess with a soft cloth. Your Xiaomi Mi 9T is ready to go again. Properly repaired extends the life of the device for many years and saves significant money compared to buying a new flagship.