Disassembling the Xiaomi Mi 9 SE is a complex technical process that requires high accuracy, specialized tools and certain skills in working with small electronics. Unlike older models where the back cover was removed relatively easily, modern Mi 9 series devices are assembled using a large amount of glue and have a complex multi-layer design.
Before you start physical intervention, you need to be aware of the risks: self-disassembly almost always leads to the loss of the official warranty. The sealed housing after opening is almost impossible to restore at home, making the device vulnerable to dust and moisture. However, if you are confident in your abilities and have the necessary equipment, this guide will help you go from a closed device to a complete dismantling of components.
It is important to understand that inside the smartphone Xiaomi Mi 9 SE all components are very tight. Any careless movement can damage the plumes or cracks on the glass back.The process requires patience, as some screws can be hidden under stickers or plugs, and adhesive connections require preheating.It is critical not to overheat the center of the case above 80-90 degrees, so as not to damage the display matrix or the battery itself.
Tools and workplace preparation required
Good workplace preparation is key to successfully disassembling and maintaining the integrity of all microscopic parts. You will need not only a set of screwdrivers, but also tools to work with adhesive joints. Without proper preparation, you can easily damage the case or lose small screws, which in the Xiaomi Mi 9 SE have different lengths and threads. Organize the space so that the light falls evenly without creating glare on glass surfaces.
To work, you will need the following set of tools and consumables:
- 🔥 Hair dryer (construction or household with a narrow nozzle) for softening the glue around the perimeter.
- 🔪 Thin metal scalpel or special blade for opening the body.
- 🧲 Magnetic mat or organizer for sorting screws of different sizes.
- 🧤 Suction cup for neat pulling back cover or display.
- 🧴 Isopropyl alcohol or special solvent of glue (B-7000) cleaning.
Prior to any work, the battery should be discharged to about 20-25% to minimize the risk of fire in case of accidental damage, it is also recommended to use an antistatic bracelet or regularly touch grounded metal objects, so as not to damage sensitive electronics with a static discharge.
☑️ Preparation for disassembly
Removal of the rear glass panel
The first and most important step is to dismantle the back cover, which in the Xiaomi Mi 9 SE model is glued around the perimeter. The heating must be uniform so that the glass does not burst from the thermal shock. Move the hair dryer along the contour of the device, lingering at the corners where the glue is usually the most. Don't direct hot air to one point for too long.
After sufficient warming up (usually 2-3 minutes), gently insert the suction cup into the bottom of the back cover and slightly pull up, creating a small gap. Insert a thin plastic card or a shoulder blade into the resulting gap. Move the tool along the edges, gradually cutting the glue layer. Be extremely careful in the area of the main camera module so as not to damage the optics or plumes.
⚠️ Attention: The glass in the back cover is very fragile. When you're under excessive pressure with a shoulder blade or uneven heating, it can crack radially from the center or at the edges. If you feel strong resistance, add a little more heat, but don't use brute force.
When the glue is passed around the perimeter, take your time to remove the lid completely.There may be thin plumes inside connecting buttons or antennas to the main board, although in the Mi 9 SE the main switch is on the bottom plume. Carefully lift the lid and inspect the insides for unexpected connections before full separation.
Dismantling the protective panel and access to the battery
When you take the back cover off, you'll see a plastic shield covering the battery and the bottom of the smartphone, and it's mounted with a lot of small screws of different calibers, and the screw system here is complex, some of them holding the board down, others fixing the lid itself, and you have to twist them out in sequence and remember the location.
Use a screwdriver with a suitable sting (usually a Torx T4 or T5) to keep the screw caps from licking. After unscrewing all the visible screws, carefully remove the plastic pad, underneath which you will see the battery itself, closed with another protective film or information sticker, as well as a plume going to the motherboard.
The next step is to turn off the battery plume, which is a critical point, because you can't use the electronics under voltage, you can use the plastic blade to push the connector up, and you can't use the metal tools here to avoid short circuits on the board.
Nuances of battery adhesive layer
Removal of the battery and replacement of components
In the Xiaomi Mi 9 SE, the battery occupies a significant part of the internal volume and is often fixed with double-sided tape. To extract it, it is recommended to warm up the battery area with a hairdryer again (not much!) or use special hoods-suction hoods. It is extremely dangerous to smack the battery with metal objects from below.
If your goal is to replace the screen, then after removing the battery and turning off all the plumes (display, touchscreen, front camera, speaker) you can move to dismantle the frame itself with the display. Often the display module is glued into the middle frame, and change it more conveniently with the frame, transferring the motherboard and the rest of the nodes.
When installing a new battery, make sure that the contact area on the plume is clean. If you change the display, check for a protective film on the back of the new matrix - it must be removed before assembly, otherwise the heat sink will be disturbed and the screen may overheat.
💡
Use pre-cut adhesive strips to fix the new battery, which will provide a reliable attachment and make future repairs easier, unlike liquid glue, which is difficult to remove.
Working with the motherboard and camera module
The motherboard in the Xiaomi Mi 9 SE is located at the top of the case and is closed with a metal screen that is also soldered or secured by screws. Removing this screen requires jewelry accuracy and, preferably, the presence of soldering equipment. Under the screen are the main processors and memory.
The main camera module here is quite large and can be attached separately. When removing it, be careful with the lenses - even a microscopic speck of dust on the inner surface of the lens will spoil the quality of the photos. The camera connects through wide plumes that require careful shutdown.
The table below shows the main components that require attention in deep disassembly, and the type of their attachment:
| Component | Type of attachment | Risk of damage | Tool. |
|---|---|---|---|
| Back cover. | Perimeter adhesive layer | Tall (glass cracks) | Fen, spatula |
| Battery | Double-sided scotch | Critical (fire) | Suction, alcohol |
| Screen. | Glue + screw frame | High (matrix breakdown) | Heat, sucker. |
| Maternity fee | Screws + plumes | Medium (steer break) | Torx screwdriver |
When working with the motherboard, never touch open contacts with your fingers, because fat and sweat can oxidize the compounds over time. You only do this when the battery is completely off. If you see oxides or traces of moisture, use an ultrasound bath and specialized chemistry, but this is the level of professional service.
Assembly of the device and verification of functionality
The assembly is done in reverse disassembly order. However, there are nuances: new adhesive strips must be positioned correctly, and screws twisted with the right force. The retraction of screws in the plastic case of the Xiaomi Mi 9 SE can lead to cracks on the inside of the frames.
Before you finish the case, make sure you run a test run, plug in the display and battery plume, then press the power button, check the touchscreen, vibrations, sound and cameras, and if everything works correctly, you can turn off the power and complete the assembly.
To restore the tightness (at least partial) use a quality adhesive B-7000 or special moisture pads. Apply the glue with a thin strip, let it dry a little (2-3 minutes), then tightly press the parts of the body and lock with rubber bands for 1-2 hours until completely dry.
⚠️ Warning: Do not turn on your smartphone immediately after assembly if you have used a lot of liquid glue.Adhesive vapors can condense inside on boards and cause a short circuit.Let the device dry.
💡
The build quality directly affects the durability of the repair, a poorly glued screen will luft, and untwisted screws will lead to crickets and noises when working.