The Xiaomi Mi 9T, known in the Chinese market as the Redmi K20, has become a hit thanks to its bezel-less design and outgoing front camera.However, the lack of a notch in the screen has made the design more difficult to maintain than conventional models. Owners often face the need to replace broken glass, battery or plumes, which requires a complete dismantling of the device.
The process of disassembling this machine requires high accuracy and patience, since the body is made of glass on both sides, and the internal components are very tightly arranged. Any careless movement can damage the plumes or crack the back cover. In this article, we will look at each stage of dismantling in detail, so that you can perform the repairs efficiently and safely.
Before starting work, you need to prepare a workspace with good lighting and do not forget about electrostatic safety. The accumulated charge on the body can disable the sensitive electronics of a smartphone, so it is highly recommended to use an antistatic bracelet or periodically touch grounded metal objects. Also make sure that you have all the necessary tools listed below.
Tools and workplace preparation required
Quality preparation is the key to successful repair. To work with the Xiaomi Mi 9T, you will need a specialized tool set, since standard screwdrivers will not be enough. Particular attention should be paid to tools for working with adhesive joints, since the back panel is attached to a very strong double-sided tape.
You will need the following tools:
- 🔥 Dryer or thermostole for heating the edges of the body to temperature 80-90 degree.
- 🔧 A set of cross-bat screwdrivers (PH000, PH00) hexagonal.
- 🪒 Plastic mediators, suction cup and thin metal spatula (or string) for opening.
- 🧲 Magnetic mat for sorting screws of different sizes.
The organization of the workspace is critical. Spread the screws in the order in which you twist them so that you don't confuse them when you build them. Long screws screwed into short holes can break through the board or damage other components, which will lead to irreversible consequences.
⚠️ Attention: Before starting the disassembly, be sure to turn off the smartphone and remove the tray SIM-Working with the device on may cause a short circuit when disconnecting the connectors.
Check the integrity of all tools. Metal blades should not have a serrated denture that can damage the glass. If you use a hair dryer, watch the temperature so that the display or battery does not overheat, which can cause them to bloat or yellow spots on the matrix.
Removal of the rear glass panel
The most difficult step in the initial stage is to carefully separate the back cover. In the Xiaomi Mi 9T model, it is glued around the perimeter with a powerful adhesive compound. Start by heating the edges of the body with a hairdryer, warming all four sides evenly for 2-3 minutes. Don't hold the hairdryer too close to one point to avoid local overheating.
After warming up, apply a suction cup to the bottom of the back cover and pull up slightly, creating a small gap. Insert a plastic mediator or a thin string into the resulting gap. Move around the perimeter, gradually cutting through the glue layer. Be especially careful in the area of the camera module and fingerprint scanner where the plumes are located.
When working with glue, it is important to take your time. If you feel strong resistance, add a little more heat. Sharp movements can cause the glass to burst. Once the lid is separated, put it in a safe place, underlaying the soft fabric to avoid scratching on the glossy surface.
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Remains of old adhesive from the frame of the case and the new back cover are conveniently removed with isopropyl alcohol and a plastic card. Do not use metal blades to clean the frames, so as not to damage the antenna inserts.
Dismantling the protective plate and disconnecting the plumes
When you take the back cover off, you'll see a massive graphite-metal shield covering most of the components, and it's secured by a lot of screws of different calibers, and your job is to unscrew all the visible screws that hold this plate and remove it carefully.
Under the plate are the connectors that need to be turned off in a strict sequence, the first thing you do is disconnect the battery plume, which is a critical step that shuts down the device and makes it safe to continue, and then you can turn off the plumes of the display, the main camera and other modules.
Use a plastic blade or nail to turn off the connectors. Do not use metal tools to avoid damaging the contacts on the board. Some connectors can be fixed with additional latches that need to be gently bent.
The main elements that need attention at this stage are:
- 🔋 Battery plume (disconnected first!).
- 📱 Display plume (main and additional).
- 📸 Camera plumes (main and module with motor).
- 📡 Antenna cables (require careful removal from latches).
⚠️ Warning: Never pull the wires of the plumes themselves. Only disconnect the plastic connector, otherwise you risk breaking thin current tracks inside the cable.
Once all communications are shut down, the protective plate can be removed completely, and now the internal components, such as the motherboard, the battery and the speaker, are fully open, and visually inspect the board for oxides or mechanical damage.
Battery extraction and glue handling
In Xiaomi Mi 9T battery is located at the bottom of the body and is also attached to the adhesive base. Remove it with utmost care, as damage to the lithium polymer battery can lead to fire or chemical burn.
Use suction hoods or plastic cards to stick them under the battery. Movements should be smooth, without jerking. If the battery is very tight, you can use isopropyl alcohol by putting a few drops under the edge of the battery to dissolve the glue. However, make sure that the liquid does not get on the board or into the connectors.
| Parameter | Meaning | Note |
|---|---|---|
| Type of battery | Li-Po | Removable, requires care. |
| Capacity | 4,000 mAh | Nominal capacity of the model |
| Heating temperature | 80-90 °C | To soften the glue |
| Heat time | 3-5 minutes | Depends on the thickness of the glass. |
The old battery must be disposed of in accordance with environmental regulations. Do not throw it in the usual garbage can. When installing a new battery, make sure that the contact area is clean, and apply a new adhesive base or a special glue B-7000 for fixation.
☑️ Pre-assembly check
Replacement of the display and module with the camera
If you wanted to replace a broken screen, you'd need to remove the metal frame that holds the display. In the Xiaomi Mi 9T, the display is glued to the middle bezel, and often the entire module is changed with the frame, which makes the assembly process much easier. However, you can try to reglaze the glass if the matrix is intact.
To remove the frame, you need to twist all the screws around the perimeter and in the center of the board. Notice the plume that goes to the control board. It's very thin and easily torn. When you install the new module, make sure that the protective films from the connectors are removed and the frame is injected with quality two-way tape.
The engine mechanism is located at the top and connected by a flexible plume to the motherboard. When disassembling, this plume passes through narrow channels, and it is easy to damage. Gently snap the locks and remove the module, trying not to touch other components.
What to do if the camera mechanism is jammed?
When you build, make sure that all the screws of the frame are twisted evenly. The skewed frame can cause the rear window to not stand in place or will press on the display, creating rainbow spots. Check the camera mechanism before the final gluing of the body.
Assembly of the device and verification of functionality
The assembly is done in reverse order, but requires even more care. Start by installing the battery and connecting its plume, then carefully stack all the other plumes in the channels intended for them, so that they are not clamped when you install the protective plate.
Secure the metal plate with screws. Make sure each screw is in place. Then you can plug the smartphone into the charger and check it without sticking the back cover. Check the touchscreen, sound, vibration, camera performance (especially the pull-out mechanism) and proximity sensors.
If all functions are working correctly, apply a new layer of glue or double-sided tape to the frame of the case. Carefully apply the back cover and evenly press it around the perimeter. For better fixation, you can use rubber harnesses or put the smartphone under a small load for 1-2 hours.
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Final inspection of all systems before gluing the case saves time and nerves, eliminating the need to re-disassemble in the event of a defect.
After drying the adhesive, wipe the fingerprint case and turn on the device for the final test. Successful replacement of components will extend the life of your Xiaomi Mi 9T for several more years of active use.