The broken rear window of the Xiaomi Mi 9 Lite smartphone is not only an aesthetic problem, but also a potential threat to internal electronics. Dust, moisture and small particles of glass can get inside the device, causing closure or damage to the plumes. That is why many owners decide to replace the rear panel themselves to save time and money on the services of the service center.
The dismantling process requires care, as the glass panel is attached to a strong double-sided tape and requires preheating. Wrong actions can damage the housing or, worse, cause the battery to fail. In this article, we will discuss in detail all the steps of preparation and removal of the lid, paying special attention to safety.
Before you start disassembling, you need to make sure that you have the right tools and conditions to work with. Safety comes first, so make sure you work on a clean, flat surface in good lighting. Lack of haste and attention to detail are the main keys to successfully repairing your gadget.
⚠️ Warning: Before any manipulations, be sure to turn off the device. Working with the smartphone on significantly increases the risk of short circuit.
Tools and workplace preparation required
To perform the job of removing the back cover, you will need a specialized set of tools that can be found in radio parts stores or ordered online. The use of improvised tools such as knives or thick needles is strongly discouraged, as they easily damage the internal components or break the glass even more.
The main tool for heating is a hair dryer. It is best to use a professional temperature-adjusted thermo-air soldering iron, but in extreme cases, a household hair dryer will also work, although the process will take longer. It is important not to overheat the body, so as not to damage the plastic frame or display on the back side.
You will also need suction cups to lift glass and thin plastic blades (mediators), metal tools can not be used, as they can damage the battery or plumes, and prepare a container for small screws, so as not to lose them in the process of operation.
- 🔥 Hair dryer or thermo-air station for heating glue.
- 📱 Glass lifting suction cup or vacuum holder.
- 🛠️ A set of plastic mediators and shoulder blades for opening.
- 🧴 Isopropyl alcohol or special solvent of glue (B-7000).
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Use high concentration isopropyl alcohol to dissolve the glue – it evaporates quickly and does not conduct electricity, which is safe for electronics.
Safety technique when working with the battery
The most important element to be careful about is the lithium-ion battery. In the Xiaomi Mi 9 Lite, it takes up a significant portion of the interior space and is located just below the back cover. Damage to the battery shell can cause it to ignite or even explode, so be extremely careful.
When you heat the case, watch the temperature. If you feel that the smartphone is getting too hot for the hand, stop heating and let it cool down a little. Excessive heating can cause the battery to bloat or damage the adhesive layer of the display on the front side.
Never try to tamper with the glass if it is not already warmed up enough, this will cause the glass to crack, and the fragments can get inside the case, and avoid deep penetration of the blade into the body - the depth of the tool should not exceed 3-4 mm.
⚠️ Warning: If you notice a bloating battery or smell chemicals, stop working immediately and put the device away to a safe place.
Work in a well-ventilated environment, especially if you use chemical solvents to remove old glue. Some substances can be toxic when inhaled in high concentrations. Use safety glasses to keep small pieces of glass from getting into your eyes.
The process of heating and separation of the rear panel
The first step of disassembly is to soften the adhesive layer that holds the back cover. Turn on the hair dryer and set the temperature at about 80-100 degrees Celsius. Direct the hot air flow to the perimeter of the back cover, moving the hair dryer around in a circle so that the warm-up is uniform.
You need to warm for about 2-3 minutes, constantly checking the temperature with your hand. The body should become hot, but not burning. Then quickly but carefully attach the suction cup at the bottom of the back cover, closer to the logo, and slightly pull upwards, creating a small gap.
Insert a thin plastic mediator into the gap, and without removing it, slowly start to move along the side edges, cutting the glue layer. If you feel strong resistance, warm up the area again with a hairdryer. Don't use force, the glue must be smooth.
- 🌡️ Warm up the perimeter evenly, lingering at corners.
- 👐 Check the temperature with your hand every 30 seconds of heating.
- 🔪 Move the mediator horizontally, parallel to the plane of the screen.
Pay special attention to the top of the smartphone, where the camera is located. There the glue can be applied with a thicker layer, and it requires additional care to avoid hitting the plumes of the camera modules. Move slowly, centimeter by centimeter, releasing the lid.
Disabling the plumes and the final removal of the cover
When the adhesive layer is passed around the perimeter, take your time to remove the lid completely.Inside, at the top of the case, there are plumes connecting the main board to modules on the rear. In the Xiaomi Mi 9 Lite model, this can be a fingerprint scanner plume (if it is embedded in a button or panel) or antenna contacts.
Carefully lift the lid a few millimeters and inspect the insides. If you see thin plumes running from lid to board, they need to be turned off. Use a plastic blade or nail to lift the locking connector up.
Once you've shut down all the connections, you can completely remove the back cover, put it down on the soft cloth with the outside, so you don't scratch the remaining glass or logo, and now you have access to the battery and the main board.
⚠️ Warning: The plumes are very thin and fragile. Don't pull them or bend them at a sharp angle, or they may break.
☑️ Ready to remove the lid
Comparison of opening methods: heating and chemistry
There are two main approaches to removing glass lids: thermal and chemical. The thermal method described above is standard and safest for beginners. The chemical method involves the use of special solvents that are introduced into the gap, but it requires more experience.
The table below compares these methods so you can choose the best one for your situation. For the Xiaomi Mi 9 Lite, heating is recommended, since the design of the body involves tight fitting of glass around the perimeter.
| Parameter | Thermal method (Fen) | Chemical method (alcohol/solvent) |
|---|---|---|
| Safety for Electronics | High (when controlling temperature) | Medium (risk of fluid intake) |
| Difficulty of implementation | Low. | Tall. |
| Time for preparation | 3-5 minutes | 10-15 minutes (waiting for reaction) |
| Risk of glass damage | Minimum | Medium (aggressive chemistry) |
Chemicals are only justified if the glass is already shattered and there is nothing to heat, or if the glue is so old and stiff that heating doesn't help. In 95% of cases, a conventional hair dryer is enough to replace the lid with a Mi 9 Lite.
What to do if the glass is cracked in your hands?
Removal of glue residues and preparation for assembly
Once the old lid is removed, the old glue remains on the frame and on the new part, and must be removed carefully so that the new panel is flat and securely maintained, and use a plastic card or spatula to scrape off large pieces.
For the final cleaning, wipe the frame with a cotton disc dipped in isopropyl alcohol. The surface should be perfectly smooth and fat-free. Don't leave the villi from the cotton can create bumps.
Apply a new layer of glue to a new lid or to the frame. You can use special adhesive tapes (B-7000, T-7000) or ready-made adhesive frames, which are sold separately. Spread the adhesive evenly and let it dry a little (1-2 minutes) before the final installation.
- 🧹 Carefully remove all old glue residues until smooth.
- 🧼 Degrease the surface with alcohol for better adhesion.
- ⏳ Let the new glue dry a little before pressing.
After applying the glue, combine the cover with the body, making sure that all the holes under the camera and speakers match. Press tightly around the perimeter and lock the device with rubber bands or a load for 15-20 minutes to polymerize the glue.
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High-quality cleaning of the frame from old glue is a guarantee that the new lid will not peel off and backlash in the future.