Modern smartphones like the Xiaomi Mi 9 SE have a compact body and powerful hardware, but their design often complicates self-repair. Owners face the need to replace a broken screen or worn-out battery, but the dense layout inside requires caution and an accurate understanding of the sequence of actions.
The disassembly process begins with evaluating the condition of the device and purchasing the necessary parts. Adhesive joints used by the manufacturer for sealing require preheating to avoid damaging the glass when opening. Ignoring this step can lead to cracks in the back cover or damage to the internal plumes, making further repair impossible or economically impractical.
In this article, we will take a detailed look at each stage of dismantling, from the removal of the tray. SIM-You will learn how to properly disconnect the plumes of the display and battery to avoid short circuits, and will also give recommendations on the use of suction cups, mediators and thermophene for safe work at home.
Preparation of the workplace and tools
Quality preparation is the key to successful repair. To disassemble the Xiaomi Mi 9 SE, you will need not only a standard set of screwdrivers, but also specific tools for working with adhesive joints. The workplace must be well lit, and the surface must be clean and antistatic, so that small screws do not get lost and electronics are not affected by statics.
The main tool will be a set of precision screwdrivers, including cross bits of the size of PH000 and PH00, which are the screws that attach most internal components, and it is also critical to have a metal blade or scalpel to tamper with the frame, but use them with utmost care so as not to damage the aluminum body or internal cables.
- 🔧 A set of precision screwdrivers (cross and flat)
- 🌡️ Thermostole or industrial dryer for heating glue
- 🧲 Magnetic screw-sorting mat
- 🧤 Antistatic gloves and tweezers
Special attention should be paid to the heating equipment. 9 SE It's glued all around the perimeter, and a cold opening is almost guaranteed to destroy it. 80-90 degrees Celsius, so as not to damageOLED-display on the back and do not deform the plastic frame.
Primary dismantling and heating of the housing
The first step is always to get the tray out of the SIM-This action not only frees up space inside, but also prevents accidental damage to the tray when the housing is heated, and then the device must be turned off completely, making sure that the screen is out and the vibration confirms that the system is working.
The heating process requires patience. Warm up the perimeter of the back cover evenly for 3-5 minutes. Movements should be circular, without delaying the hair dryer at one point, especially in the area of the chamber where the sensitive optical modules are located. Thermocleus should soften to a state where the suction cup easily pulls the glass, creating a gap.
⚠️ Warning: Don't try to tear off the back cover by force unless it moves away.Inadequate heating will cause the glass to break or damage the plume of the fingerprint scanner that runs under the lid.
Once there is a minimum gap, a thin mediator or plastic card is immediately inserted into it. Move around the perimeter, cutting the adhesive layer. Metal tools are not recommended, as they can scratch the inner frame or, worse, damage the battery if the blade goes too deep.
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Use a suction cup not only to pull it back, but also to hold the lid up while you're working as a perimeter mediator, which will reduce the risk of the glue sticking again.
Removing the back panel and protecting the battery
Once the back panel is successfully detached, you can access the internal components, and immediately under the lid you'll see a metal wireless charging plate (NFC) and a main motherboard that's covered with a decorative lid, but the first thing you need to do is to keep the system power-free.
In the Xiaomi Mi 9 SE, the battery plume is connected directly to the motherboard. Before removing any metal screens or unscrewing the screws, you need to turn off the battery connector. This will prevent accidental short circuit that can occur when the tool comes into contact with the board.
Use a plastic blade to turn off. Metal tweezers are dangerous because of the risk of contact breakdown. Carefully put the connector up, trying not to damage the connector itself on the board. Once turned off, the device is considered completely de-energized, and you can proceed to further disassembly.
- 🔋 Disconnect the battery plume first.
- 🛡️ Use only plastic tools to work with connectors
- 🧹 Remove the glue residue from the frame before a new assembly
- 🧪 Degrease the frame surface with alcohol for better grip
If you're planning to replace the battery, you can carefully remove the plume after you turn off using special pulling strips or warming up the back of the case, but most often disassembly is required to access the display, which requires removing the protective metal screens.
☑️ Safe disassembly
Dismantling of protective screens and modules
And underneath the back, there's a massive metal plate that covers most of the electronics, and it's mounted with a lot of screws of different sizes and lengths, and it's critical to remember or record the location of each screw on the magnetic mat, because screwing a long screw into a short hole can actually cut through the motherboard.
After you unscrew all the screws (usually about 15-20 pieces), you remove the metal frame, which allows you to access the top and bottom plumes of the display, as well as the main camera connector, and there is a charging connector, which often needs to be replaced.
When removing metal screens, look for hidden screws that may be under stickers or warranty seals. In the Mi 9 SE, some screws can be hidden under Near Field Communication (NFC) decorative elements.
⚠️ Warning: Metal screens often have thin pins that are pressed against the board.When removing and installing, make sure these pins are not bent and positioned correctly, or there may be problems with the signal or antennas.
Now that access is open, you can disconnect the plumes of the display, they are fixed by special pressing plates, first the screws that hold the plates are unscrewed, then the plume is carefully raised. Sharp movements are unacceptable — microscopic contacts on the plume are easily damaged.
Replacement of the display and touch screen
The Xiaomi Mi 9 SE uses AMOLED technology, where the display and touchscreen are a single module glued to the frame. Replacing only glass (touchscreen) at home is almost impossible without professional separation equipment, so replacing the module assembled with or without a frame is considered.
If you bought a frameless module, you need to transfer all the components from the old screen to the new one, which includes a speaker, a vibrator, button plumes and a camera, and each action should be accompanied by a check of the integrity of the plumes. Be especially careful with the bottom board plume that runs through a narrow channel.
When installing a new module, make sure it sits tightly in the slots. The gaps can lead to dust or moisture. After connecting the plumes (but before final assembly), it is recommended to conduct a test turn on.
| Component | Type of attachment | Risk of damage | Tool. |
|---|---|---|---|
| Back cover. | Glue B-7000/T-7000 | High (glass break) | Fryer, sucker. |
| metal frame | PH000 screws | Medium (carving break) | Screwdriver, tweezers. |
| Display plume | Pressure plate | Critical (contact break) | Plastic spatula |
| Battery | Glue + connector | High (puncture, bloating) | Heat, sucker. |
If you successfully catch the MI logo, you're going to have to check the density of the connectors if the screen doesn't light up, and sometimes you have to reconnect them twice to make the contacts fall into place.
What to do if the screen is stripped after replacement?
Assembly of the device and checking leakage
The final step is assembly. It's done in reverse order, but with the addition of new adhesives. The old adhesive needs to be carefully removed from the housing. You can use isopropyl alcohol and soft fabric. The surface needs to be perfectly clean and fat-free.
A new layer of special electronics glue (e.g., B-7000) is applied to the frame, or a double sticky tape cut along the contour is glued; the layer of glue should be uniform, without bubbles and interruptions, to ensure proper tightness. After pressing the back cover, it is desirable to fix the device with rubber harnesses for 30-60 minutes.
Once the glue is dry, check all the functions: touchscreen, cameras, speakers, microphones and proximity sensors. Make sure the fingerprint scanner responds quickly and accurately. If everything works correctly, you can consider the repair complete.
- 🧼 Carefully clean the frame of the old glue
- 🧴 Apply the new glue evenly around the perimeter
- ⏱️ Let the glue dry under pressure (shores)
- 📱 Test all functions before the final cleaning.
You should not ignore the sealing test, although complete waterproofness as in the factory is difficult to achieve. Quality gluing will protect the device from splashes and dust, extending its service life after repair.
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The quality of the repair depends on 80% accuracy of cleaning the frame and uniform application of new glue.
Frequent mistakes in self-disassembly
Even skilled craftsmen make mistakes, let alone beginners, and one of the most common problems is that the plume of the underscreen fingerprint scanner is damaged, and it's very thin, and it runs close to the edge of the body, and if you do a sloppy autopsy, it's easy to tear it up, and then the scanner stops working.
Another mistake is losing or entanglement of screws. As mentioned earlier, screws of different lengths can penetrate the board or the case, and often forget to plug the plume of the volume and on buttons, which makes it impossible to turn on or adjust the sound after assembly.
⚠️ Warning: Never plug or disable the display and camera plumes when the battery is connected, guaranteed to cause the power controller or backlight on the motherboard to burn.
The use of inappropriate adhesives, such as superglue (Second), is strictly prohibited. Cyanacrylate vapors settle on the optics of cameras and sensors, irrevocably clouding them, and the glue itself becomes brittle and does not hold the lid when heated.