Modern smartphones are becoming more difficult to maintain, and the Xiaomi Redmi Note 9 is no exception. Owners often face the need to replace broken glass, worn-out battery or charging plume, which requires careful opening of the device. However, improper actions during dismantling can lead to damage to internal components or loss of warranty, so it is important to strictly follow proven algorithms.
The process of disassembling the Redmi Note 9 requires patience, special tools and understanding of the design of the gadget. In this article, we will take a detailed look at each step, from the preparation of the workplace to the final assembly, to minimize the risks, you will learn what nuances hides the rear panel and how to safely disconnect the plumes without using aggressive methods.
Before you start, make sure you have all the tools and free time you need, and haste is the master’s main enemy, especially when it comes to fragile electronics, and proper preparation will avoid typical mistakes and preserve the integrity of all elements of the smartphone.
Tools and workplace preparation required
The quality disassembly begins long before you pick up the first tool, and you need to create a clean, well-lit space where the small parts are not lost or damaged, and the ideal solution is to use an antistatic mat that protects the board from static electricity.
To work with the Redmi Note 9, you will need a specific set of tools that can be purchased in specialty stores or ordered online.
- 🔧 Precision screwdrivers (cross-haired) PH000 and flat) for screw twisting.
- 🌡️ A hair dryer or thermophen to soften the adhesive layer under the cover.
- 🎴 Plastic blades (mediators) and suction cup for safe opening of the body.
- 🧲 Magnetic mat or container with screw sorting cells.
- 🧤 Thin tweezers for working with small connectors and plumes.
Special attention should be paid to the condition of the battery before work. If the battery is swelled, you should exercise utmost caution, as damage to its shell can lead to fire, in such cases, it is recommended to use protective glasses and gloves.
⚠️ Warning: Never start disassembling if the battery level is above 25%.Working with high voltage lithium polymer batteries increases the risk of short circuit if the plume is accidentally damaged.
☑️ Preparation for disassembly
Removal of the rear glass panel
The back cover of Xiaomi Redmi Note 9 is made of glass and glued around the perimeter with a special sealant. To remove it without chipping or cracking, you need to preheat the adhesive layer. This uses a hair dryer that should be kept at a distance of 3-5 cm from the body for 2-3 minutes.
The heating temperature should not exceed 80-90 degrees Celsius, otherwise you can damage the display or internal plastic elements. You can check readiness by carefully trying to tamper with the edge of the cover with a mediator - if it enters with effort but without creaking, the glue is softened.
After warming up, insert the suction cup into the bottom of the back panel, closer to the logo, and slightly pull up, creating tension. At the same time, without letting go of the suction cup, insert a plastic spatula into the resulting gap and move it along the perimeter, cutting the adhesive layer.
- 🔄 Move slowly in a circle, warming up difficult areas with a hairdryer as needed.
- 🚫 Do not use metal blades or knives as they easily cut through the glass and can damage the plumes underneath it.
- 👀 Keep an eye out for the camera module location – in this area, the adhesive layer is often thicker and requires longer heating.
When the lid is separated from the frame, don't try to remove it completely immediately. Inside, there may be thin plumes connecting buttons or a fingerprint scanner (if integrated into the lid, although in this model the side scanner is) Carefully place the panel in a safe place.
What to do if the cover is broken when removed?
Dismantling internal components and protection of boards
When you take the back cover off, you see the inside of the smartphone, and you have a battery in most of the space, and at the bottom of the back is a motherboard that's covered with a black plastic cover, and you have to twist some screws around the perimeter of that protection to access the board.
If you confuse them when you build them, a long screw can penetrate the motherboard right through, which will lead to fatal consequences for the device, and it is recommended to use a circuit or take photos of each stage.
When you take off the plastic protection, you'll see the main connectors connected to the board, and the first thing you need to do is turn off the battery to turn off the system, and then you need to gently tuck the battery connector with a plastic blade or nail, moving parallel to the board plane.
| Component | Location. | Type of attachment | Features of dismantling |
|---|---|---|---|
| Battery | Central part | Glue + connector | Requires heating and use of plastic cards |
| Maternity fee | Lower third | Screws + connectors | Fragile plumes, requires caution |
| Camera module | Upper left corner | Glue + connector | Complex optics, you can not touch the lenses |
| Dynamician | Lower corner | Screws + connector | Often comes in the assembly with a charging connector |
Then you disconnect the plumes of the display, the cameras and other modules. When working with the connectors, avoid sudden jerks. If the connection does not respond, check if there is a locking plug or an additional screw.
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Use a magnifier or macro image of the phone to take a picture of the plume's location before turning off, which will help avoid errors in reverse assembly.
Replacement of the battery and work with the glue layer
In the Redmi Note 9, the battery is glued to the frame rather firmly, which is the standard for modern smartphones. To extract the old battery, it must be heated on the back side (through the display if it is removed, or through the back cover if it is intact, but in our case the cover is already removed, so warm carefully along the battery circuit).
Apply a small amount of alcohol or a special liquid (such as a B-7000) under the edge of the battery using a syringe with a thin needle. This will help dissolve the glue. Then carefully enter a plastic card or a special string under the battery and, with sawing movements, separate it from the frame.
⚠️ Warning: It is strictly forbidden to use metal tools to smack the battery.Puncture of the cell causes instant ignition and toxic smoke.
After removing the old battery, carefully clean the seat of glue residues. The surface should be smooth and clean so that the new battery will lie flat and hold secure. You can use special adhesive tapes (B-5000/B-7000) or double-sided electronics tape to fix it.
Install a new battery, making sure its connector matches the connector on the board. Don't plug it in right away -- first make sure all the plumes are in place and nothing is stopping you from closing.
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Proper preparation of the seat and use of high-quality glue ensure that the battery will not swell due to poor heat sink and hold tightly in the case.
Assembly of the device and verification of functionality
The assembly is done in reverse disassembly. First, connect the battery, then plug the display, cameras and other modules. Once the battery is connected, check if the smartphone is turning on before you twist all the screws and glue the lid.
If the device is switched on, check the touchscreen, cameras, microphone, speaker and vibrations, make sure the proximity sensor and fingerprint scanner are working correctly, and only after successful testing can the final fixation begin.
Apply a new layer of glue (B-7000 or analog) around the perimeter of the frame with a thin continuous line. Avoid getting glue inside the case, on the cameras or into the connectors. Apply the back cover and press it tightly around the perimeter.
- 🕒 Let the glue dry during 1-2 hours, fixing the body with rubber bands or load (without pressure on the screen).
- 🧹 Remove the excess glue that has protruded outside until it has frozen completely.
- 🔌 Put it in. SIM-map and check the operation of communication modules.
The final step is to clean the case of fingerprints and check the tightness of the lid, and if done correctly, the smartphone will look and work like a new one.
Typical errors and troubleshooting
Even experienced craftsmen sometimes make mistakes, let alone beginners, and one of the most common problems is that the backlight plume is damaged when the lid is not neatly removed, and if the screen is lit after assembly, but the image is not, it is likely that this plume or its connector is damaged.
Another common mistake is that the touchscreen is damaged when pressed on the screen during battery detachment, and if the touchscreen is no longer responsive to touch in certain areas, it may have been deformed, and in such cases, a complete replacement of the display module is required.
Also, users often forget to clean the connectors before installation, oxidation or dust can cause the camera or sensor to work unstable, and wipe the contacts with dry soft cloth or special liquid.
⚠️ Warning: If the smartphone doesn't turn on after assembly, don't try to charge it right away. Check the battery plume connection and no short circuit on the board.
If you see artifacts on the screen or spontaneous reboots after you change the battery, check if the display plume is framed, sometimes it's enough to loosen the screws a little or reconnect the connector.