The Xiaomi Redmi 9 is a challenge faced when replacing the battery, repairing the camera, or cleaning the dust, but the back of the device is not only attached to the latches, but also to the adhesive layer, and fragile plumes are laid underneath. Wrong actions can lead to cracks in plastic, breakage of contacts or even damage. NFC-antenna located under the upper part of the body.
In this article, you will find detailed instructions tailored to the Redmi 9 (codenamed lancelot), a list of tools you need and unique techniques for safely separating the lid without heating, and we will also analyze common mistakes that beginners make and give recommendations for reverse assembly.
If you've never taken a smartphone apart before, it's important to understand that it takes patience and care. Even professionals sometimes have difficulties with the individualities of the adhesive joint, but with the right approach, the risks are minimized.
Preparation: tools and modalities
Before you start, make sure you have everything you need. The minimum set includes:
- 🔧 Plastic mediators (2-3 pc, thickness 0.2–0.4 mm) to separate the cover without scratching.
- 🔥 Hair dryer or thermoair station (not necessary, but recommended for softening glue).
- 🧲 Suction cup (3-5 cm in diameter) – helps to create an initial effort to separate the cover.
- 📏 Thin screwdriver (cross, for screws under the cover).
- 🧴 Isopropyl alcohol (90%+) — glue-cleaner.
Work on a flat, clean surface with good lighting. If you use a hair dryer, adjust it to a temperature no higher than 60°C so that you don't damage the plastic or the display. Don't use metal tools to separate the lid, they leave scratches and can close contacts on the board.
⚠️ Warning: If your Redmi 9 was in high humidity, dry it in rice or silica gel for at least 24 hours before disassembling. The glue under the lid can retain moisture, which will lead to corrosion of the contacts.
Also prepare a screw container (such as a magnetic mat or a plastic box with cells). The screws in Xiaomi Redmi 9 are of different lengths, and confusing them when assembled is a common mistake.
Step 1: Power out and tray removal SIM-map
Before disassembling, be sure to turn off the smartphone and remove the tray for SIM-This will prevent the contacts from accidentally closing and damage to the board, and the tray is removed using a paper clip or a special key that is included in the kit.
If the battery is swelling (which often happens after 2-3 years of use), do not try to remove the lid by force. The bloated battery can burst or ignite when mechanically exposed.
Turn off the smartphone|Remove the tray SIM-map|Check the battery for bloating|Prepare tools|Provide good lighting-->
Whether or not you heat your smartphone before disassembling it depends on the glue condition. If the lid hasn't been removed before, the glue will be strong, and it's hard to do without heating, and if you've already disassembled the device, you can try without a hair dryer.
Step 2: Rear cover separation – technique and nuances
Start at the bottom edge of the smartphone (near the USB-C connector). Here, the adhesive layer is thinner, and the risk of damage to the plumes is minimal. Apply the suction cup closer to the center of the bottom and pull up slightly to create a gap.
Insert a plastic mediator into the resulting gap and carefully guide it along the edge, gradually separating the lid. Do not exert excessive force - if the lid does not lend itself, stop and heat the edge with a hairdryer for 1-2 minutes.
- 🔥 Heating temperature: 50-60°C, keep the hair dryer at a distance of 5-7 cm.
- ⏱️ Heat time: no more than 30 seconds per site.
- 🚫 It is forbidden to heat the area of the chamber or NFC-antennas (top part of the cover).
When the lid starts to detach, don't remove it completely right away. NFC-The antennas that are attached to the motherboard, and you can only remove the lid completely once they're unplugged.
What to do if the lid is cracked?
| Section of the lid | Risks in disassembly | How to avoid |
|---|---|---|
| Lower edge (USB-C) | Damage to the charging plume | Separate slowly, without jerking |
| Upper edge (camera) | The cliff NFC-antennae | Don't heat this area with a hairdryer. |
| Side sides | Plastic cracks | Use mediators, not screwdrivers |
| Cover angles | The latches can break. | Starting the division from the center, not from the corners |
Step 3: Unconnect the plumes and completely remove the lid
When the lid is separated around the perimeter, gently lift it up, but don't remove it completely.
- 📶 schleife NFC-antennas (thin black cable at the top).
- 👆 Fingerprint scanner plume (if your model is equipped with it).
- 🔋 Battery (glued to the body, do not try to remove it without special devices).
To unplug the plumes, use plastic tweezers or a mediator. Tuck the connectors carefully and unplug them from the motherboard. Don't pull the wires, it can break the contacts.
Now you can take the lid off completely. If the glue is left on the case or the lid, remove it with isopropyl alcohol and soft cloth. Don't use acetone or solvents, they will damage the plastic.
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If the train NFC-The antennas are gone, so don't rush to buy a new cover, so you can solder the antenna back to the service center if the contacts on the board are intact.
Common Mistakes and How to Avoid Them
Even experienced users sometimes make mistakes when disassembling the Redmi 9.
- Metal tools. Metal conducts current and can close contacts on the board. Always use plastic or wooden mediators.
- Overheating. Temperatures above 60°C warp plastic and can damage the battery. Warm up in short intervals.
- Sharp lid separation, which causes plumes to break or crack, and move slowly, 1-2 mm at a time.
- Tangled screws when you build them, screws of different lengths, if you screw a long screw into an undesignated place, you can damage the board.
Another common problem is damage to the adhesive layer under the battery, so if you're planning to reassemble your smartphone, don't remove all the glue, leave some to re-adhesive, or use a 0.5mm double-sided 3M tape.
⚠️ Warning: If the smartphone doesn't turn on after disassembly, check: Connect the battery plume (it could have left when the lid was removed) the integrity of the contacts on the motherboard (it may have been closed with static electricity). Try connecting the charger – if the charging indicator lights up, the problem is not in the board.
Reverse Assembly: Tips for the Perfect Result
Assembling Xiaomi Redmi 9 after repair requires no less care than disassembly.
- 🧩 Check all the plumes before you install the lid. They should be tightly connected to the connectors.
- 🔄 Remove the old glue from the lid and case. Use alcohol and cotton swabs.
- 📏 Level the cover before the final pressing. gaps greater than 0.5 mm indicate improper installation.
- 🔨 Twisting the screws cross-cross to avoid distortions.
If you've been replacing your battery, don't turn on your smartphone right after assembly. Give the glue (or tape) to grab for 10 to 15 minutes. Then plug in the charger and check if the battery is recognized by the system.
To check the performance of NFC after assembly:
- Install the NFC Tools app from Google Play.
- Bring the smartphone to NFC-tag (for example, a bank card).
- If the application does not respond, check the antenna connection.
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If there are gaps between the lid and the body after assembly, the cause may be an improperly installed battery or skewed screws. Take the smartphone apart and repeat the assembly.
When is the best time to contact the service center
Despite the apparent simplicity, disassembling the Xiaomi Redmi 9 can be a daunting task.
- 🔋 The battery is swollen or deformed.
- 📱 The display cracked or moved away from the body.
- 🔌 After disassembly, the smartphone does not turn on or charge.
- 📡 antenna NFC The fingerprint scanner has stopped working.
The cost of dismantling in the service usually does not exceed 500-1000 rubles, but you will avoid the risk of damaging the device. If you disassemble a smartphone to replace the battery, note that the original battery for Redmi 9 costs about 1500-2000 rubles, and the analogue - 800-1200 rubles. Savings on self-repair can turn into additional costs if something goes wrong.
Also remember that Xiaomi warranty does not apply to devices with traces of self-repair. If your smartphone is still warranty, it is better to contact an authorized service center.