The Xiaomi Mi 9, which launched in 2019, is still a popular device thanks to its powerful processor and high-quality camera. However, over time, even reliable technology requires intervention: broken glass, a worn-out battery or problems with a vibrator make you think about repairing. Self-disassembly is a difficult but economically viable step, if you have the necessary tools and patience.
The process of opening the body of the Mi 9 is significantly different from the older Mi models due to the use of a glass rear panel and the absence of a 3.5 mm jack. The adhesive base here plays the role of not only a sealant, but also a structural element. Any careless movement can damage the internal plumes or chipped glass, so it is important to strictly follow the sequence of actions.
In this article, we will discuss the component dismantling algorithm in detail, focusing on the adhesive layer and fragile connectors, what tools will be required to safely open the device and how to avoid damaging the display when the back cover is separated.
💡
Before starting work, be sure to back up all data, as the repair process may require a complete reset of the device or accidental deletion of information.
Tools and workplace preparation required
A screwdriver is not enough to disassemble a smartphone properly; you need a specialized toolkit that allows you to work with miniature screws and fragile components. The suction cup is a critical element, as it creates the initial gap between the case and the frame.
Pay special attention to the choice of medical alcohol or special solution B-7000 for softening the glue. Use of aggressive chemicals or water is unacceptable, as this can damage the oleophobic coating of the screen or cause corrosion of the board. Also prepare a plastic blade that will not scratch the glossy surfaces.
- 🔧 Torx screwdriver set (T5, T6) cross-block (PH000) scalable.
- 🔥 Dryer or thermostole to heat the back panel to a safe temperature.
- 🛠️ Plastic mediators and metal thin scalpel for tweaking components.
- 🧲 Magnetic mat for sorting screws, so as not to confuse them when assembling.
Organize the space so that nothing distracts you. Good lighting is not just a convenience, it is a necessity to see microscopic connectors. Dust and static electricity can become enemies, so it is advisable to use an antistatic bracelet or regularly touch a grounded metal object.
☑️ Ready to disassemble
Removal of the back cover and primary access
The first step is always to turn off the power. Even if the phone is off, there may be a residual charge on the board that can short-circuit the tools in contact with the components. SIM-maps to provide air output when heated.
Heating the back is the most important thing. The Xiaomi Mi 9 glass conducts heat unevenly, so you need to heat around the perimeter, avoiding the center where the camera and battery are located. The temperature should not exceed 80-90 degrees Celsius, otherwise there is a risk of damage to the display matrix from the back side.
⚠️ Warning: Don't overheat the body! If you keep the hair dryer too long at one point, the glue can boil and stain the internal components, and the glass can burst from temperature shock.
After warming up (usually 2-3 minutes), fast but gently glue the suction cup at the bottom of the back cover. Pull up to create a gap, and immediately insert a plastic card or blade into the slot. Driving the tool along the faces, gradually cutting through the glue layer. Do not enter the tool deeply so as not to touch the tail of the side button or antenna contacts.
What to do if the lid does not move?
Dismantling the protective plate and disconnecting the plumes
Once you successfully remove the back cover, you will see an interior space that is enclosed by a black protective plate made of composite material or metal, and this plate covers the main components: the motherboard, the battery and the camera module, and you will need to unscrew many small screws around the perimeter to remove it.
Swirling a long screw into a hole for a short one can pierce the board through, with fatal consequences for electronics.Use a magnetic mat or circuit to remember the location of each fastener.
When you remove the plate, don't be in a hurry to disconnect the connectors immediately. First, you need to remove the plastic lining, which further fixes the plumes. To turn off, use a plastic blade or nail, gently lifting the connector up. Metal tools here are better not to use, so as not to damage the contacts on the board.
- 🔋 Turn off the battery connector first, de-energizing the device.
- 📱 Carefully disconnect the display plume, holding it by the metal part of the connector.
- 📸 Remove the connectors of the main and front cameras modules.
- 📶 Disable antenna cables if they interfere with further access to nodes.
Once all communications are off, you can start removing the motherboard, which is usually locked in the slots, so you need to sway it slightly from side to side, and be careful with the plume of the lower speaker, which often passes under or near the board.
💡
The order of shutting down the plumes is strictly regulated: first power, then periphery.
Replacement of the battery and work with adhesive base
In the Xiaomi Mi 9, the battery is located at the bottom of the case and is mounted on double-sided tape throughout the area, which is made for better heat transfer and fixation, but it is very difficult to replace. It is impossible to pull the battery out just like that - there is a high risk of damage to it, which can cause lithium to ignite.
To safely extract, you need to use the heat again. Heat the area around the battery (not the battery itself directly!) and use special suction hoods or a thin line / string. The line is wound behind the battery and cut the adhesive layer with sawing movements.
The new battery must be installed on fresh double-sided tape. The use of liquid glue (B-7000) to fix the battery is strictly prohibited, as the next repair will not be possible to remove it without the risk of explosion.
| Parameter | Old battery | New battery | Norma. |
|---|---|---|---|
| Capacity | Less than 3,000 mAh | 3300 mAh | 3300 mAh |
| Voltas | 3.85 V | 3.85 V | 3.85 V |
| Status. | Bloated/Weared | Dense/New | Free of deformities |
| Date of production | Older 3 years | Fresh. | Less than 6 months. |
After installing a new battery, be sure to check the voltage on the contacts with a multimeter before connecting to the board.This will help make sure that the battery is not defective and is not in deep discharge. Connect the plume and make sure that the phone responds to the press of the on button.
Replacement of the display and the touch screen module
If your goal was to replace a broken screen, the process is complicated by the fact that the Mi 9 uses a broken screen. AMOLED-It's almost impossible to change the glass and the matrix separately at home without special equipment (separator and laminator.
To replace it, you have to move all the internal components from the old frame to the new one, which includes the motherboard, batteries, cameras, charging boards and even the speaker, and it's a time-consuming process and requires care, because the number of screws and plumes is so large.
⚠️ Warning: When you re-paint parts to a new frame, make sure the speaker mesh is clean and the microphone holes are not clogged with glue. Otherwise, you will have sound problems.
The new display module also has factory adhesive around the perimeter. Before setting the frame in the case, you need to check the screen performance by temporarily connecting the plumes. If the image is clean, without stripes and the touch screen reacts, you can proceed to the final assembly. Carefully put the plumes in the designated channels so that when the cover is closed, they do not clamped.
Pay special attention to the proximity sensor, which is at the top of the screen. If you move the frame or leave a gap when you build, the sensor may not work properly and the screen will not go out during the conversation. Make sure that the protective film from the internal sensors is removed.
Assembly of the device and verification of functionality
The final step is reverse assembly, and it's done in reverse disassembly, first you put a protective plate in and screws in, then you plug in the battery, and then you can put the new glue on the body after you've checked the performance.
Use a special electronics adhesive sealant (e.g., B-7000 or T-7000) to seal the frame, apply a thin, uniform strip along the perimeter of the frame, avoiding the adhesive from the camera, speaker and connectors. Excessive glue exposed to the outside should be removed immediately before it freezes.
After applying the glue, press the back cover and lock the smartphone with rubber rings or a load for 1-2 hours, which is necessary to polymerize the composition and create a reliable connection. The full strength of the glue is gained after 24 hours, so on the first day it is better not to expose the phone to loads.
- ✅ Check the operation of all buttons (volume, on) for sticking.
- ✅ Test the communication module by inserting SIM-map and check the signal.
- ✅ Take a test photo on all cameras, including the front.
- ✅ Check Wi-Fi, Bluetooth and GPS module.
Successful assembly is confirmed by the absence of gaps between the glass and the frame, as well as the stable operation of all functions. If after assembly the phone warms up or discharges quickly, there may be a short circuit or a screw that creates pressure on the board.