How to Disassemble Xiaomi 3S independently: detailed instructions with nuances

Xiaomi Smartphone 3S (also known as the Mi 3S The Mi 3 Enhanced Edition is a 2014 iconic model that is still used by many users, but as the device ages, it is common to have a battery that is dead, a faulty speaker or a cracked screen. Disassembling the phone may be necessary to replace components, clean dust or diagnose malfunctions. In this article, we will discuss in detail how to properly dismantle the Xiaomi case. 3S, What tools will be needed and what to pay attention to to avoid damaging fragile components.

It is important to understand that disassembling a smartphone is a process that requires accuracy and patience. 3S This is not a modular device, which uses adhesives, thin plumes and miniature screws, and disassembly errors can damage flexible cables, tear off contacts, or even cause the motherboard to fail. If you have never taken a smartphone apart before, we recommend that you first practice on a less valuable device or consult a professional.

In this manual, we took into account all the nuances of Xiaomi design 3S, Including the location of the hidden latches, battery attachment features, and the way the plumes are disconnected, you will also find tips for choosing tools, photos of key stages, and warnings about typical errors. Whether your goal is to replace your battery, display or speaker, this guide will help you make everything as safe as possible.

Preparation for disassembly: tools and precautions

Before starting the Xiaomi disassembly 3S, You have to prepare the workspace and the tools, and not having the right tools is one of the main causes of self-repair damage:

• 🔧 Set of screwdrivers (cross-haul) PH00, flat 1.5 Mm, five-point Torx. T3/T4 squirrel).
• 📱 Plastic mediators or shoulder blades (to separate the body so as not to scratch the frame).
• 🔥 Dryer or thermo-air station (to soften the glue under the battery and back cover).
• 🧲 Magnetic mat or organizer (so as not to lose screws and small details).
• 🔋 Screen suction cup (helps to gently lift the display module).
• 🧴 Isopropyl alcohol (90%+) (Cleaning contacts and removing glue residues).
• 📸 Smartphone for photography (fix every step so you don’t confuse the order of the assembly).

Also prepare the work surface: it should be clean, well-lit and without static electricity (a table with an antistatic mat is ideal). 3S They're of different lengths, and if you mix them up in places when you build them, you can damage the motherboard or the screen, so we recommend that you arrange them in order or sign them.

⚠️ Warning: Don't use metal tools to split the case! Xiaomi plastic frame 3S easily scratched, and the aluminum back cover can deform. Also avoid excessive heat with a hair dryer - temperatures above 80°C can damage the battery or display.

Step 1: Turn off the phone and remove the back cover

The first step is to turn off the power and dismantle the back panel, and although it seems simple, there are a few nuances:

1. Turn off the phone and remove it. SIM-card and memory card (if installed) this will prevent short circuits when working with the board.
2. Stick a protective film (such as scotch) on the screen to avoid scratching when using a suction cup.
3. Heat the back cover with a hair dryer for 1-2 minutes, holding it at a distance of 10-15 cm. the glue under the cover will soften, and it will be easier to remove.
4. Insert a plastic mediator into the gap between the lid and the frame (start at the lower right corner where the latches are located). Carefully drive the mediator around the perimeter, separating the lid.

Xiaomi's back cover 3S It's mounted on 8 screws (4 on each side) and adhesive tape around the perimeter, and it's hidden under rubber plugs, so you need to tweez them carefully with a needle or tweezers, and when you take the lid off, you'll see the battery, the camera and the antenna modules. Do not pull the cover sharply - it is connected to the board by a flexible antenna plume (it must be disconnected from the later).

Turn off the phone and remove the cards

Put a protective film on the screen

Heat the cover with a hair dryer (1-2 minutes)

Push the mediator from the lower right corner

Unscrew 8 screws under rubber plugs-->

If the lid doesn't lend itself, don't use excessive force, you better warm up the problem areas with a hair dryer again. In some cases, the glue can be too strong (especially if the phone was not taken out of the factory), in which case the isopropyl alcohol applied around the perimeter by the mediator will help.

Step 2: Disconnect the battery and plumes

When the back cover is removed, the first thing you do is turn off the battery. This is critical: even a phone that is turned off can get a short circuit when you touch the board. 3S The battery is glued to the body, and its dismantling requires caution.

Algorithm of action:

1. Unscrew 4 screws that fix the metal plate over the battery.
2. Carefully attach the battery connector with a plastic mediator (it is located at the top of the battery) and disconnect it from the board.
3. If the battery is swollen, do not try to pierce or bend it, this can lead to fire, in which case it is better to replace the battery immediately.
4. To remove the battery, warm it with a hair dryer (no higher than 60).°C) and pull on a special black tape (pull-tab), if it is preserved.

Once the battery is turned off, you can start disconnecting the plumes. 3S several:

• 📞 Display plume (the widest, located at the bottom of the board).
• 🔊 Touchscreen plume (thin, next to display plume).
• 📷 Main camera plume (at the top of the board, under a metal screen).
• 📡 The antenna plume (connects the back cover with the board, disconnects lastly).

⚠️ Attention: Trains in Xiaomi 3S Don't pull them by the wires, just by the plastic connectors. If the contacts are oxidized, clean them with isopropyl alcohol, not sandpaper.

💡

If the plume is not detached, do not use force! Try to gently shake it left-right with a plastic blade. Often it helps to lightly heat the connector with a hairdryer (not higher than 50).°C).

Step 3: Dismantling the motherboard and child modules

Once all the plumes are turned off, you can remove the motherboard. 3S It's mounted on 10 screws of different lengths, so we recommend taking pictures of their location or putting them in order.

Procedure:

1. Unscrew all the screws fixing the board (start with corner ones).
2. Carefully raise the fee with a plastic blade, starting from the upper edge (there are fewer plumes).
3. If the board fails, check if all screws are unscrewed - often forget about the screw under the battery.
4. After removing the board, put it on an antistatic surface (for example, on a package from components).

On the Xiaomi motherboard 3S located:

• 🧠 Qualcomm Snapdragon 800 processor (under metal radiator).
• 📶 Memory modules and flash drive (soldered to the board, non-removable).
• 🔌 Connector for connecting the charging plume (often oxidized).
• 🎤 Microphone and speaker (attached separately, on the child board).

If your goal is to replace a charger or microphone, you can disassemble them without removing the board completely. USB Type-C (in Xiaomi) 3S Micro-USB is used) is attached to 2 screws and connected to the board with a flexible plume. Be careful when replacing it - the contacts are very thin and easily break off when overheated with a soldering iron.

Step 4: Replace the screen or touchscreen

One of the most common reasons for Xiaomi’s disassembly 3S It's a cracked screen or a broken touchscreen, and in this model, the display module is three parts:

1. Glass with an oleophobic coating (the outer layer).
2. LCD matrix (responsible for the image).
3. Touchscreen (sensory layer).

In most cases, the entire module is changed (called a "display unit"), but sometimes you can only replace the glass or touchscreen.

• 🔥 Hair dryer or heat plate (to soften the glue around the perimeter of the screen).
• 🧊 A gel pack or cold compress (to quickly cool the glue after heating).
• 📏 Suction cup and plastic mediators (for careful separation of glass).
• 🧴 Special glue (e.g., glue, B-7000) glass-stick.

Screen replacement process:

1. Heat the display with a hair dryer (temperature 70–80)°C) for 3-5 minutes, evenly driving around the perimeter.
2. Suction the screen from one of the corners (usually start from the bottom).
3. Insert a plastic mediator into the resulting slit and carefully lead it along the edge, separating the glass from the frame.
4. After the glass is separated, disconnect the display and touchscreen plumes (as described in Step 2).
5. Install a new display module, connect the plumes and glue the glass to a new glue.

⚠️ Warning: When heating the screen, do not point the hair dryer to one area for too long - this can damage the LCD matrix (spots or stripes will appear). Also avoid moisture under the glass: even a small drop can cause corrosion of the plumes.

1. Correctness of connection of the plume (it should click when fixing).

2. No damage to the plume (scratches, tears).

3. Compatibility of the new display module with the Xiaomi model 3S (Sometimes Chinese analogues are not suitable).-->

Step 5: Replace the battery

Battery is one of the most vulnerable parts of Xiaomi 3S. After 5-7 years of operation, the battery capacity drops by 30-50%, and in some cases the battery swells.

Here's how to do it right:

1. Turn off the old battery (as described in Step 2).
2. If the battery is glued, warm it up with a hair dryer (no higher than 60).°C) and pull the black tape (pull-tab). If there is no tape, gently tuck the battery with a plastic blade on the side.
3. Clear the place of installation of the new battery from glue residues (use isopropyl alcohol).
4. Install a new battery, connect the plume and fix it with double-sided tape or special glue.

When choosing a new battery, pay attention to:

• 🔋 Capacity – the original battery Xiaomi 3S It has a capacity of 3050 mAh.
• 🔌 Type of connector - must coincide with the original (in some replicas, the connector can be turned over).
• 📏 Sizes - even a small discrepancy will lead to deformation of the body.
• 🔍 Controller: Cheap batteries without a controller fail quickly.

After replacing the battery, it is recommended to calibrate it:

1. Charge your phone to 100% and hold on charging for another 1-2 hours.
2. Discharge until automatic shutdown.
3. Repeat the cycle 2-3 times.

💡

If the new battery is discharged quickly, check the battery consumption in the settings (Settings) → Sometimes high consumption is caused by a board malfunction or background processes, rather than by the battery itself.

Step 6: Build your phone and check its health

Assembling Xiaomi 3S after disassembly should be in reverse order, but taking into account a few important points:

• 🔧 Screw them in the same order that you screwed them out, screws of different lengths, and if you mix them up, you can damage the board.
• 🧲 Trains -- make sure all connectors are fixed before you click. Pay special attention to the touchscreen plume, which often falls out.
• 🔋 Battery – before final assembly, check that it is connected and the phone is turned on.
• 📶 Antenna – don’t forget to connect the tailgate of the back cover, otherwise the network signal will deteriorate.

After assembly, perform a check:

1. Turn on the phone and check the screen (are there any broken pixels, stripes).
2. Test the touchscreen (responsiveness, multi-touch).
3. Call your phone to make sure the microphone and speaker are working.
4. Connect the charging and check if the current is coming (the indicator should catch fire).
5. Make sure the cameras (main and front) focus and don't produce artifacts.

If something doesn't work after assembly, don't panic. Go back to the appropriate step and check:

• Are all the plumes connected (especially the touchscreen and display).
• Is the battery skewed (this can put pressure on the board and cause failures).
• Are there any other items (screws, pieces of glue) left under the payment?

⚠️ Warning: If the phone doesn't turn on after assembly, but the indicator is on when charging, the problem may be an incorrectly connected power plume or a damaged board.

Frequent Mistakes and How to Avoid Them

Even experienced masters sometimes make mistakes when disassembling Xiaomi 3S. Here are the most common ones and how to prevent them:

Another common problem is that the flexible plume of the camera is damaged, and it's very thin, and it often breaks when it's not properly removed, and if the camera doesn't work after assembly, check:

• Is the camera plume connected to the board?
• Is there any visible damage to it (breaks, creases).
• Is it not a stained stain (if necessary, clean it with alcohol)?

If you damage the plume, it can be replaced, but it requires soldering work, and in most cases it is easier to buy a new camera module (it is inexpensive and sold on AliExpress or in service centers).

FAQ: Answers to Frequent Questions