How to disassemble the Xiaomi Mi Band 4 fitness bracelet without damage: instructions with photos and warnings

The Xiaomi Mi Band 4 fitness bracelet is one of the most popular wearables, but even it is not immune to breakdowns. Over time, you may need to replace the battery, repair the display or clean the contacts, and this requires careful disassembly of the body. Unlike newer models (for example, the Mi Band 6 or 7), the fourth version has its own design features, which are important to consider so as not to damage the fragile elements.

This article will help you disassemble the Mi Band 4 yourself, minimizing the risks. We will describe the necessary tools, step-by-step procedure, and also warn you about the typical errors that lead to the failure of the device. If you have never repaired electronics, we recommend you to carefully study each step - especially the section on disconnecting the plumes and working with the adhesive connection.

Preparation for disassembly: tools and security measures

Before you start, make sure you have everything you need, the wrong tool is the main cause of damage to the body or internal components, and here is the minimum kit you'll need:

• 🔧 Plastic mediators or shoulder blades (thickness 0.2-0.4 mm) - for careful opening of the body without scratches.
• 🔥 Hair dryer or thermoair station (optional) - if the glue is too strong, the body can be slightly heated (not higher than 60)°C!).
• 🧲 Magnetic screwdriver. T3 or T4 — for unscrewing screws (in some batches of bracelets, screws can be under a cross screwdriver).
• 📦 Tweezers with thin ends - for working with plumes and small details.
• 🧴 Isopropyl alcohol (90%+) — Cleaning contacts and removing glue residues.
• 📸 Smartphone with camera – to capture the location of parts before disassembly.

Also, prepare the workplace: the desk should be clean, well-lit and without static electricity (ideal to use an antistatic mat). There is no removable battery inside the Mi Band 4 - it is soldered to the board, so replacing the battery will require soldering or the use of special adapters.

⚠️ Warning: If the bracelet is warranty, disassembly will cancel it. Xiaomi service centers refuse to repair after self-opening the case.

Step 1: Removing the strap and opening the body

The first step is to separate the bracelet capsule from the strap, and the Mi Band 4 uses a latch mechanism that is different from the newer models (like the magnetically fastened Mi Band 5).

1. Turn the bracelet with your display.
2. Find a small recess on the back of the capsule next to the charging connector.
3. Insert a plastic mediator into this recess and gently press the strap side until you hear a click.
4. Repeat the action on the other side of the capsule.

If the strap doesn't lend itself, don't use excessive force, you can break the plastic locks. Try swaying the mediator slightly left-right, pulling the capsule on yourself at the same time. Once you remove the strap, you'll see two screws under the lid (in some versions, they can be hidden under the sticker).

Step 2: Unscrewing the screws and separation of the front panel

The screws in the Mi Band 4 are often of different thread lengths -- remember which screw you're spinning from so you don't get confused when you build it. Use a magnetic screwdriver to keep the screws from falling or getting lost. Once the screws are unscrewed, the body will still be held on glue.

For separation of the front panel with display:

1. Place the mediator in the gap between the front and back of the case (start from the side opposite the button).
2. Carefully swipe the mediator around the perimeter, gradually separating the parts. If the glue resists, you can slightly heat the body with a hairdryer (do not direct hot air to the display!).
3. And as soon as you hear the characteristic crack, it breaks the adhesive compound. Don't worry, it's normal.

When you split the case, you'll see a plume of the display that connects the screen to the main board. Don't pull the plume, it's fragile and can come off the board. You'll want to disconnect it immediately with tweezers, pulling the black lock (it opens up).

Step 3: Removing the battery and working with the board

The battery in the Mi Band 4 is soldered to the board, so replacing it will require a soldering iron with a thin stinger (no more than 30 watts) and solder. If you have never soldered, it is better to entrust this stage to a professional - the risk of damage to the board is very high.

Procedure:

1. Disconnect all plumes (display, vibration motor, heart rate sensor).
2. Find two battery pins on the board – these are usually labeled as B+ and B-.
3. Carefully heat the contacts with a soldering iron and remove solder with the help of a swab or suction.
4. Put a plastic blade on the battery and remove it. Be careful, lithium polymer batteries can swell over time!

If you just need to clean the contacts or replace the display, you don't need soldering, but remember, the Mi Band 4 board is sensitive to static electricity. Only touch it with ground tweezers or with antistatic gloves.

Step 4: Replace the display or sensor

If the purpose of the disassembly is a replacement AMOLED-If you have a display, you can install a new screen after the plume is disconnected, and the main thing is to make sure that the display model is compatible with your Mi Band 4 revision (they may vary depending on the batch.

To replace the heart rate sensor:

• 🔍 Disconnect the sensor plume from the board (it is attached to a separate connector).
• 🧼 Clean the seat of dust and glue residues with isopropyl alcohol.
• 🆕 Install a new sensor and fix it with glue (for example, B-7000).

After replacing any component, check the bracelet's performance before final assembly. Connect the capsule to charging and make sure the display is turned on and the sensors respond to touch.

1. Correct connection of all plumes (they must click when fixing).

2. no short circuit on the board (look for foreign particles).

3. battery charge (if completely discharged, it may take 10-15 minutes to charge to turn on).-->

Step 5: Build the bracelet and check the leakproofness

The assembly takes place in reverse order, but there are several nuances:

• 🔄 Make sure all plumes are securely fixed in the connectors (they should click with a slight click).
• 🧩 When twisting screws do not apply excessive force - the thread in the plastic case is easily broken.
• 🌡️ If you use a new adhesive to seal it, apply it in a thin layer around the perimeter of the front panel.
• 🔋 Before final assembly, check that the battery is not swelled and is correctly located in the grooves.

After assembly, be sure to check the tightness of the bracelet.

1. Immerse the bracelet in water for 1-2 seconds (no deeper than 1 meter).
2. If you have air bubbles, you're not sealed, so take the bracelet apart and check the adhesive connection.

⚠️ Warning: Even after successful assembly, the Mi Band 4 may lose water protection.It is not recommended to swim with a bracelet after self-repair.

Common Mistakes and How to Avoid Them

User experience shows that most breakdowns in the disassembly of the Mi Band 4 occur due to the following errors:

• 🔨 Using metal tools - scratches the body and can close contacts on the board. Always use plastic or wooden mediators.
• 🔥 Overheating during soldering - soldering iron temperature above 300°C destroys the tracks on the board. Optimal range: 250-280°C.
• 💧 Getting liquid on board - even a drop of water can cause corrosion.Work in a dry place and use alcohol only to clean the board off.
• 🔋 Incorrect polarity of the battery - when soldering a new battery mixed + and – contacts will lead to a short circuit.

If the bracelet stops turning on after dismantling, don't panic. 80% of the time, the problem is solved by rechecking the plumes and contacts, and if the fee is damaged, you can try to restore it at the service center (but this is often more expensive than buying a new bracelet).

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The most vulnerable part of the Mi Band 4 is the display plume, and the cliff leads to a black screen, in which case the entire display module, not just the plume, will need to be replaced.

FAQ: Frequent questions about the dismantling of Xiaomi Mi Band 4