The process of disassembling modern smartphones requires increased accuracy, especially when it comes to the Xiaomi Redmi 9S model. The back panel of this device is glued around the perimeter, which makes its dismantling difficult for an untrained user without proper experience. Any careless movement can lead to damage to the plumes, cracks in the glass or deformation of the frame of the case.
The challenge is that the manufacturer used an aggressive adhesive to keep the structure tight and monolithic. To remove the back cover, you need to soften the adhesive with heat, but it's important not to overheat the display matrix or the battery itself. In this article, we'll go through all the preparation and execution stages in detail.
Before you begin to physically affect the body, make sure that you have the necessary set of tools at hand.The use of improvised tools such as knives or needles is strongly discouraged, as they can easily damage the internal components or break the glass when you try tampering.
Tools and workplace preparation required
And the way to do this is to start with a space, and you're going to need a clean, well-lit surface that's free of foreign objects, so you don't lose any of the screws or parts, and the ideal way to do this is to use a magnetic mat, but you're going to need a paper sheet that has a pattern of screws.
To work with the Redmi 9S, you will need a specific set of tools that can be purchased in electronics stores or marketplaces. The standard home craftsman set will not work here, since the design of the smartphone involves the use of precision tools.
- 🔥 Hair dryer or thermal pistol - necessary for uniform heating of the adhesive layer along the perimeter of the body.
- 🔪 Thin metal scalpel or special spatula - for primary penetration under glass.
- 📏 Plastic mediators (suction cups) - for safe detachment of the cover without scratches.
- 🧴 Isopropyl alcohol or special solvent of glue (B-7000) — for final cleaning and facilitation of the process.
Special attention should be paid to the heat source. A normal household hair dryer may not give enough temperature, so it is better to use a temperature-adjusted building hair dryer or a professional heating pad for smartphones. 80-90 degrees Celsius, so as not to damage OLED-matrix or not swelling battery.
⚠️ Warning: Before starting any work, be sure to turn off the smartphone. Attempting to remove the cover on the device on can lead to a short circuit and failure of the motherboard.
☑️ Preparation for the Redmi disassembly 9S
The process of heating and separation of the rear panel
The most critical step is to properly warm the body perimeter, apply heat evenly, driving the heat source in a circle at a distance of 2-3 cm from the glass surface, do not hold the hair dryer in one place for longer than 3-4 seconds to avoid local overheating.
After you have warmed up your smartphone for 2-3 minutes, you can try to gently tamper with the angle of the cover. Use a thin metal blade or scalpel, inserting it into the gap between the frame and the glass. The movement should be sliding, not stabbing, so as not to damage the plume of the fingerprint scanner, which often runs close to the edges.
Once the blade has entered the gap, insert a plastic mediator immediately. Do not leave a metal tool in the gaps, as it can transmit static electricity or damage the internal components when accidentally slipped. Next, insert new mediators, gradually move around the perimeter, cutting the adhesive layer.
💡
If the lid doesn't lend itself, don't use force. Add another 30-60 seconds of dryer warm-up, paying special attention to the corners where the glue is usually the most.
In the Xiaomi Redmi 9S, the main connections are at the top, so you can’t bend the lid at a large angle at once. First, you need to completely free all sides except the one where the connections are supposed to be.
| Heat zone | Warm-up time | Temperature. | Risk of damage |
|---|---|---|---|
| Top part (camera) | 40-50 sec. | max 80°C | Tall (optics, plumes) |
| Side edges | 30 seconds. | max 90°C | Medium (frame) |
| Lower part (dynamics) | 40 seconds. | max 90°C | Low. |
| Central part | Don't heat up | - | Critical (battery) |
⚠️ Warning: Never heat the central part of the back cover where the battery is located. Overheating of a lithium polymer battery can cause it to ignite or bloat.
When you feel the glue is soft and the lid is starting to move away, move on to using a suction cup. Stick it at the bottom of your smartphone and gently pull it up while you're cutting the glue with a mediator, a technique that allows you to control the tension and minimize the risk of glass breaking.
Disabling the plumes and removing the cover
Once the adhesive layer has been softened around the perimeter, don't be in a hurry to remove the back panel completely. In the Redmi 9S, the fingerprint scanner plume can be glued to the inside of the lid or connected to the board in a hard-to-reach location, and a sharp jerk is guaranteed to cause the plume to break.
Carefully raise the edge of the lid and visually inspect the interior space, if you see a connection, it must be turned off. Use a plastic blade or dielectric-coated tweezers. You can't use metal tools on the battery.
The connectors on the Xiaomi board are usually fixed quite tightly, and you don't need to peel them behind the wires themselves, but behind the plastic base of the connector, and the movement should be directed strictly upwards, without skewing to the sides, so as not to break the contacts on the motherboard.
What to do if the plume is broken?
Once you've shut down all the visible connections, you can finally remove the back cover, put it in a safe place, preferably on a soft cloth, so you don't scratch the glossy surface, and now you have access to the battery, the main camera module, and the charging connector.
If your goal was just to replace the battery, then most of the work is done at this stage, but if you plan to change the screen or repair the board, the process may require further disassembly of the internal components, which requires even more care.
Cleaning the case of old glue
You can't install a new lid or reassemble it without thoroughly cleaning the frames of the old adhesive, and if you leave the clumps of the old adhesive, the new panel will get bumpy, there will be gaps, and the sealing will be broken, which is critical for dust protection.
Use isopropyl alcohol or a special solution to remove the glue to remove the residues. Apply a small amount of liquid on a napkin or cotton swab and gently rub the residues around the frame. Try not to pour the liquid inside the case so as not to damage the electronics.
- 🧹 Use a toothpick to remove large lumps of glue from hard-to-reach corners.
- 🧽 Degrease the surface of the frame with alcohol before applying new glue.
- 👀 Visually check the frame for microcracks or chips.
Pay special attention to the area around the lens of the main camera. Even the smallest speck of dust or crumb of glue that gets under the camera glass during assembly will lead to black spots in the photos. Blow the insides of the pear body to clean the optics before final assembly.
After cleaning, the surface should be perfectly smooth and dry, and only after that you can start applying new glue or installing adhesive tape, if you use a ready-made remake for the Redmi 9S.
Assembly and seal check
To fix the back cover, it is best to use a special glue B-7000 or T-8000, which remains elastic after drying, or a ready-made adhesive tape cut into the shape of the body.
After applying the glue, carefully align the lid with the body, starting with the top where the plume is located. Make sure it is not pinched and lies flat. Then gradually press the rest of the lid. For better fixation, you can put the smartphone under a light load for 15-20 minutes.
⚠️ Warning: Do not turn on your smartphone immediately after gluing. Allow the glue to be fully polymerized during the period 2-4 hours, otherwise the cover may move during operation.
Checking the tightness at home is difficult, but visual inspection of the gaps is mandatory. Swipe your finger along the junction of the lid and the frame - the transition should be smooth, without steps and sharp edges. If the lid is luftitis or creaks when pressed, then the layer of glue is applied unevenly.
💡
The quality of cleaning the frames from old glue directly affects the final tightness and appearance of the assembled smartphone.
Possible problems in the disassembly
Even following the instructions, you can face unforeseen difficulties, and users often complain that the glass cracks in their hands during removal, due to uneven heating or too much pressure from the mediator on the center of the glass panel.
Another common problem is damage to the scanner plume. In the Xiaomi Redmi 9S, this component is very tensile, and if you feel resistance when lifting the lid, you haven't fully released the plume or forgot to turn off the connector.
It's also possible that the battery is damaged by a tool, and if you notice the battery bloating or you smell the electrolyte, stop working immediately, take it out into the open and dispose of it. The damaged lithium battery is a fire hazard.
In some cases, the screws under the back cover can be of different lengths. When reassembling, it is important not to confuse their places, since screwing a long screw into a short hole can penetrate the motherboard through, causing irreversible damage.