How to disassemble Xiaomi Note 3: a step-by-step repair guide

Disassembly of the Xiaomi Mi Note 3 smartphone can be required in various situations, from the banal replacement of broken glass to the installation of a new battery.This device, released in 2017, has a rather complex design with adhesive connections, which requires the master to be especially careful and have a specialized tool. Before starting any work, you need to clearly understand the risks, since inept handling of thin plumes can lead to the device failure.

The dismantling process begins with an analysis of the body design, which is made of metal with plastic antenna inserts. Unlike more modern models, there is no moisture protection, but the build density is high. The main difficulty is that the back cover is not removed in the usual way without first heating the glue. If you have never repaired mobile equipment, it is worthwhile to carefully study each step to avoid damage to the internal components.

The success of the operation depends on your preparation and the availability of high-quality tools at hand. You should not try to open the device with knives or needles, as this is almost guaranteed to lead to chipping on the frame or, worse, to damage the battery.

Tools and workplace preparation required

To properly disassemble the Mi Note 3, you need a minimal but specific set of tools that any novice craftsman will have. First of all, you will need a heating element, since the factory glue that holds the rear panel at room temperature holds the structure dead, the ideal solution would be a thermotaphele or, in extreme cases, a temperature-adjusted building dryer, although the latter requires more care not to overheat the matrix.

The second important element is the suction cup and the mediators (plastic blades), metal tools should not be used categorically, as they can short contacts on the board or damage the insulation of the plumes, and a set of screwdrivers, including cross bits of different sizes, and tweezers with curved tips for working with small screws and connectors.

• 🔥 Thermotaphel or hair dryer to soften the adhesive layer.
• 🛠 A set of precision screwdrivers (cross and slit).
• 📱 Plastic mediators and a suction cup for opening the body.
• 🧲 Magnetic mat or organizer for screws.

⚠️ Attention: Before starting work, be sure to turn off the smartphone and remove SIM-Working with the battery on when the plumes are disconnected can lead to a short circuit.

Organize the workspace so that light falls evenly and all tools are within reach. Small screws have the ability to fly around the room and get lost in the pile of the carpet, so having a magnetic mat or even a white sheet of paper will make it much easier to assemble back. Surface cleanliness is also important so that dust does not fall under the display or camera.

Removal of the back cover and primary disassembly

The first step is to heat the perimeter of the back cover. Set your smartphone on a thermotaphel at about 80-90 degrees Celsius and leave it for 3-5 minutes. If you use a hair dryer, warm the edges evenly, constantly moving the hot air flow so as not to create local overheating that can damage the screen on the front side. You can determine the readiness of the glue by slightly pulling the suction cup: if the lid starts to move even slightly, then the temperature is reached.

Once warmed up, attach the suction cup to the bottom of the back, closer to the Xiaomi logo, and gently pull up to create a small gap. Insert a plastic mediator into the resulting gap immediately. Don't try to remove the lid with a jerk, this will lead to cracks. Slowly guide the mediator along the perimeter, cutting the softened adhesive layer. Pay special attention to the corners where the glue is usually the most.

When the lid is completely detached, remove it and put it in a safe place, and you will see the interior of the device, immediately notice the massive block of the main camera and the metal protective plate covering the plumes, and at this stage it is important not to damage the plume of the fingerprint scanner, which can be glued to the inside of the lid or carefully placed in the designated place.

Dismantling protective plates and disconnecting plumes

Inside the case of the Xiaomi Note 3, you'll see several metal plates screwed up by screws that protect the connectors of the display, battery and other modules from mechanical damage and dust. To access the main components, you need to unscrew all the screws that attach the center and side plates. The number of screws can vary, so watch their length carefully, as it can vary from place to place.

Once you remove the metal, you'll see the connectors, and the first thing you need to do is turn off the battery plume, which is a critical step that shuts down the device and makes it safe to do that, and use a plastic blade or nail to gently lift the connector up. Don't pull the plume, just the hard part of the connector.

Then you detach the display and touchscreen plumes, and they can be attached to additional latchers that you need to bend, and once you turn off all the cables, you can completely remove the protective plates and put them aside, and now access to the main nodes is open, and you can start replacing specific components.

💡

When unscrewing the screws, spread them out in the order in which they were removed. screws of different lengths can fall into the wrong holes and damage the board when screwed in.

Replacement of the battery and work with glue

In the Mi Note 3, the battery is located at the bottom and is closed with an additional protective frame and plumes. To get to it, you often have to dismantle the vibrator motor and even the lower board. The battery here is planted on a two-way scotch, which over time tans, but when heated becomes sticky. Use a thin plastic card or a special string to extract the old element, carefully cutting the adhesive layer.

Never try to rattle a battery with a screwdriver or a knife! A puncture of a lithium polymer battery will cause instantaneous fire or explosion. If the battery is dead, add some alcohol to it through a thin syringe, wait a couple of minutes and try again. After removing the old element, thoroughly clean the landing site of glue residues with alcohol and degreaser.

Installing a new battery requires fresh adhesive. Use special adhesive tapes (B-7000 or striped analogues) to ensure reliable fixation and replacement. Don't overdo it with the amount of glue, excess glue can squeeze out and stain the internal components. After installation, connect the plume and check the charging before final assembly.

• 🔋 Heat the case to make it easier to remove the battery.
• 🚫 Use only plastic tools to work with battery.
• 🧹 Carefully degrease the surface before sticking a new element.
• ✅ Check the voltage on the contacts before closing the case.

⚠️ Warning: If the battery is swelling, treat it very carefully. Bloating indicates a violation of the chemical processes inside, and pressure on such a cell can lead to ignition.

Importantly, the Mi Note 3 battery is closed with a metal frame that needs to be unscrewed, making the replacement process more time-consuming than the models with a removable back cover.

Removal of display and replacement of glass

Replacing the display module in the Xiaomi Mi Note 3 is one of the most difficult operations. The screen is glued around the perimeter, and it requires reheating the front part. If you change the module assembly (with a frame), the task is simple: you just need to move all the insides to a new frame. If you change only the glass or matrix without a frame, you will need a separator and a special liquid to remove the adhesive (LOCA/OCA).

To remove the old screen after heating, carefully poke it around the perimeter with a mediator. Move slowly, trying not to damage the side edges of the metal frame. Inside are plumes that run under the frame, so sudden movements are unacceptable. After removing the old panel, clean the frame from the glue residues to perfect smoothness, otherwise the new screen will lie uneven or will peel off.

When you install a new module, apply a thin layer of special glue for the screens or use a pre-glued adhesive. Combine the connectors, connect the plumes and gently press the module against the frame. For better adhesion, you can use rubber harnesses to pull the phone together for 15-20 minutes, which will ensure uniform fit and no air bubbles.

💡

The quality of the glue and careful cleaning of the frame is the guarantee that the new screen will not go away with time and dust will not get into the gaps.

Assembly of the device and verification of functionality

The Xiaomi Mi Note 3 is assembled in a strictly reverse sequence. Start by putting all the internal components in their places, making sure that the plumes are not clamped down and lie in their channels. Pay special attention to the fingerprint scanner plume: it is very thin and easily breaks when laid out carelessly. All screws twist without undue effort, so as not to break the thread in the plastic bushings.

Before you stick the back cover, make sure you run a test run, plug the battery, press the power button, and check the touchscreen, sound, vibration and cameras. If everything works correctly, you can apply new glue to the body. Use a quality sealant glue (such as the B-7000) by applying it with a thin strip around the perimeter.

Press the back cover and hold it with harnesses or loads for the time the glue is drying (usually 1-2 hours). After solidifying completely, wipe the case of glue residues and turn on the smartphone for final inspection. Successful assembly means that you saved a significant amount of money on services of the service center and gained valuable experience.

• 🔍 Visually check all connections before closing.
• 🧪 Conduct a touch screen test (drawing figures in the menu).
• 🔊 Check the speaker and microphone.
• 📸 Take a test photo on both cameras.