Xiaomi Redmi 12 is one of the most popular budget smartphones of 2023, but even it is not immune to breakdowns. Whether it’s a broken screen, a dead battery or a faulty speaker, sooner or later the owner may need to disassemble the device. However, improper disassembly often leads to damage to the plumes, cracks in the case or even a complete failure of the phone.
In this article, we will discuss how to safely disassemble the Redmi 12 at home, what tools you need, what to look for when working with adhesive joints, and how to avoid typical errors. This guide is suitable for both replacing the battery or screen, and for diagnosing internal components. If you have never disassembled a smartphone before, don’t worry: with the right approach, even a beginner will cope with the task.
Preparation for disassembly: tools and precautions
Before you start disassembling, make sure you have everything you need. Xiaomi Redmi 12 has adhesive back mount and brittle plumes, so you can’t do without specialized tools. Here’s the minimum set:
- 🔧 Plastic mediators (2-3 (S) for a careful sleeve of the lid.
- 🔥 Dryer or thermo-air station - for softening the glue (temperature 60-80)°C).
- ⚙️ Torx screwdriver T3 and T4 — medium-frame screw.
- 📱 Suction - helps to lift the cover after heating.
- 🧲 Magnetic mat or container – to avoid losing small screws.
- 🔍 Loop or magnifying glass - for inspection of small details.
If you are planning to replace the battery, add an insulating film (to avoid short circuits) and a new adhesive to fix the lid. Don't use metal tools to tamper with the lid, they will scratch the body and can damage the plumes!
⚠️ Warning: If you're disassembling a phone with a damaged screen, be sure to put tape on it so that shards of glass don't get inside the case or hurt you. Also note that Redmi 12 has hidden latches under the volume and power buttons - they are easy to break when you open sloppyly.
Step 1: Removing the back cover – how not to damage the adhesive joint
The most important step is to separate the back panel. In the Xiaomi Redmi 12, it is glued around the perimeter, and also fixed with plastic latches near the buttons and USB-C connector. If you pull the lid by force, you risk tearing off the fingerprint scanner plume or damaging antenna contacts.
Algorithm of action:
- Turn off the phone and remove it. SIM-map.
- Heat the back cover around the perimeter with a hair dryer (keep it 5-7 cm away so you don't overheat). Pay special attention to the corners and areas near the chamber.
- Suction hold closer to the bottom edge (where the USB-C connector is) and gently pull up.
- Insert a plastic mediator into the resulting gap and slowly lead it along the body, separating the glue.
If the lid doesn't lend itself, don't force it, you better warm up the problem area again. Typical mistake is trying to separate the lid from the top edge (there are camera plumes and fingerprint scanners). Always start from the bottom!
Warm up with a hair dryer for 2-3 minutes|Use the suction cup for the initial lift|Put the mediator in the slot|Take your time to remove the glue gradually|Check if the fingerprint scanner plume is clinging.-->
Step 2: Unscrew the screws and remove the middle frame
Once you remove the back cover, you'll see 12 screws that lock in the middle frame. In Redmi 12, they're of different lengths, so remember or photograph their location before you unscrew them. Use the Torx T3 screwdriver for most screws and the T4 screws for the two screws near the charging connector.
The middle frame is not only on the screws, but also on the plastic latches.
- Unscrew all the screws and fold them into a magnetic container.
- Carefully tuck the frame with a plastic mediator on the side (where the volume buttons are).
- Lift the frame and move it towards the screen - it should come out of the slots.
| Type of screw | Number of | Location. | Length (mm) |
|---|---|---|---|
| Torx T3 | 10 | The perimeter of the middle frame | 3.5 |
| Torx T4 | 2 | Near the USB-C connector | 4.0 |
| Torx T3 (black) | 2 | Under the battery (motherboard fastening) | 2.8 |
⚠️ Warning: Don't mix screws up when you reverse assemble! 4.0mm screws (at the connector) USB-C) If you screw in other holes, you can damage the motherboard. If in doubt, use a marker to mark them before unscrewing them.
Step 3: Battery Disconnection – Why You Should Do It First
Before any manipulation of the internal components, be sure to turn off the battery. In Redmi 12, it is connected through a plume with a JST 1.0 connector, which is easily damaged if removed sloppy. Use a plastic tweezer or mediator to gently lift the connector.
How to disconnect the battery:
- 🔋 Find the battery plume (usually black or orange, located at the bottom of the board).
- 📍 Put the connector on the side with a plastic tool - it should come out of the nest with a slight click.
- ⚡ Check with a multimeter that there is no voltage on the board contacts (optional, but recommended for safety).
If the battery is swelling, don't try to puncture it or bend it, it can cause fire, in which case you should trust the replacement to the professionals, and also pay attention to the insulating film under the battery: if it is torn, replace it before installing the new battery.
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If the battery connector is stuck and does not detach, do not pull it by force. Drink a little isopropyl alcohol (90%+) on the contacts and wait 1-2 minutes - this will help dissolve the oxides.
Step 4: Removing the motherboard and other components
After the battery is turned off, you can start dismantling the motherboard. In Redmi 12, it is attached to 4 Torx T3 screws (two of them are hidden under a metal protective plate) and double-sided tape in the area of the chamber.
Procedure:
- Unscrew all screws, including those under the protective plate (it is attached to the latches).
- Then, turn the right hand over to the right hand side and put it in the right hand.
- Disconnect all plumes: 📸 Main and front cameras. 🔊 Dynamician and microphone. 📶 Antenna contacts (they are fragile - do not pull the wires!).
If you're disassembling a phone to replace a USB-C connector or a charging controller, be careful: these elements are soldered to the board. They will require a soldering station and experience with microelectronics. At home, it's better to limit yourself to diagnosing or replacing removable components (speaker, vibrator, cameras).
What to do if the camera plume is broken?
Step 5: Replacing the screen – the nuances of working with the Redmi 12 display
The screen in Xiaomi Redmi 12 is one of the most vulnerable places. When replacing the display, it is important to consider that it is glued to the touchscreen and frame, so buy only original modules (article: MB-E0001-00 for the version with 90 Hz). Cheap Chinese counterparts often have problems with color reproduction and sensitivity.
Step-by-step:
- Warm up the edge of the screen with a hair dryer (temperature not higher than 70).°C so as not to damage OLED-matrix).
- Subdense the display with a plastic mediator on the left side (where the volume button is).
- Carefully lift the screen and disconnect the plumes: 🎨 Display plume (wide, white connector). 👆 Touchscreen plume (thin, black connector).
Install a new screen, having previously cleaned the frame of glue residues.
When gluing the new screen, use double-sided 3M 9448A tape or B-7000 liquid glue. Don't forget the pads under the screws - they prevent the plumes from clamping. After assembly, check the touchscreen in the service menu (#6484##).
Common Mistakes and How to Avoid Them
Even experienced craftsmen sometimes make mistakes when disassembling the Redmi 12, and here are the most common ones and ways to prevent them:
- 🔧 Screw the screws – use high-quality Torx screwdrivers with a magnetic tip and do not apply excess force.
- 🔥 Overheating board – do not point the hair dryer to one area for longer than 20 seconds to avoid melting plastic parts.
- 📱 Damage to the fingerprint scanner plume – it goes from the back cover to the board, so separate the cover carefully.
- 🔋 Short circuit – always turn off the battery before working with the board and use an antistatic bracelet.
If the phone does not turn on after assembly, check:
- Correct connection of all plumes (especially the battery and display).
- Integrity of contacts on the board (sometimes they depart when heated).
- Battery charging (if the phone is discharged, it won’t turn on before connecting to the network).
⚠️ Warning: If the phone is not charging or discharges quickly after the battery is replaced, check: Conformity of new battery capacity (original - 5000 mAh). Integrity of the charging controller on the board (if it overheats, it can fail). MIUI (sometimes resetting helps).
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The most common cause of failure after disassembly is incomplete connection of the plumes. Always check that the connectors have clicked before the characteristic click.