The Xiaomi Mi 4, launched in 2014, is still popular with enthusiasts for its robust design and upgrade capabilities. However, over the years, even this brick can have problems: a discharged battery, a faulty speaker or a cracked screen. Disassembling the device is the first step to self-repair, but without knowing the nuances it is easy to damage fragile plumes or break the mounts.
In this article, you will find detailed instructions for disassembling the Xiaomi Mi 4 with photos of key stages, a list of necessary tools and unique tips for working with the adhesive layer of the rear cover, which are not available in standard manuals. We will also analyze typical beginner errors and give recommendations for safety, from antistatic protection to proper battery recovery.
Preparation for disassembly: tools and precautions
Before you start disassembling, make sure you have everything you need. The Xiaomi Mi 4 is a monolithic device where many of the elements are glued together or locked by latches. A regular screwdriver is not enough.
Here is the minimum set of tools you will need:
- 🔧 Plastic mediators (2-3 Pc.) - for careful slinging of the lid and plumes.
- 🔨 Cross screwdriver PH00 — rear-panel.
- 🧲 Magnetic mat or container – to avoid losing small details.
- 🔥 Hair dryer or thermoplatform - for softening the glue (temperature not higher than 60)°C!).
- 🧴 Isopropyl alcohol 90%+ — glue-cleaner.
- ⚡ Antistatic bracelet - mandatory when working with the motherboard!
⚠️ Warning: Do not use metal tools to pluck the back cover - the Mi 4 aluminum body is easily scratched. Also avoid overheating with a hair dryer: in temperatures above 70°C may damage the screen module.
Before starting the work, follow the following steps:
- Turn off your smartphone and remove it. SIM-map.
- Discharge the battery before 20-30% — This will reduce the risk of fire in case of accidental closure.
- Make a backup of your data (via Mi Cloud or ADB backup).
- Prepare your workspace: a clean desk, good lighting, no carpets (static electricity!).
Removing the back cover: combating glue and latches
The back cover of the Xiaomi Mi 4 is mounted on 12 screws and double-sided tape, and the main difficulty is to carefully separate it without damaging the antenna contacts and leaving no traces on the body.
Step 1. Screwing the screws
- Turn the smartphone down with the screen.
- Unscrew all screws around the perimeter (them). 12 long 3-4 Attention: the propellers of the speaker and the camera are shorter than the others - do not confuse them when assembly!
- Place the screws on the magnetic mat in order of extraction (you can photograph their location).
Step 2. Softening the glue
Use a dryer at minimum power (or a thermoplatform with temperature) 50-60°C) and warm up the edges of the cover during 2-3 Don't point hot air at the screen, it can damage the polarization layer! Alternatively, put your smartphone on a warm battery. 10 minute.
Step 3. Separation of the cover
Put a plastic mediator in the gap between the lid and the body at the headphone jack. Carefully guide it around the perimeter, separating the glue. When resisting, do not push harder, you better warm up the problem area again. Especially carefully work around the antenna lines (upper and lower edges)!
Hammer the edges with a hairdryer (50-60°C)
Insert the mediator at the 3.5 mm connector
Carefully drive around the perimeter without jerks
Do not press the center of the cover (there is a battery!)
Check the latch separation by clicking-->
| Section of the lid | Risks of careless removal | Council |
|---|---|---|
| Upper edge (antennas) | Contact break Wi-Fi/Bluetooth | Use a mediator 0.15 mm thick. |
| Lower edge (dynamic) | Damage to the dynamics membrane | Get closer to the screws, not the grille. |
| Side sides | Aluminum shell chips | Do not use metal tools. |
| Camera angle | Damage to the camera plume | Separate the lid at an angle 15-20° |
Removing the battery: how not to cause a fire
Xiaomi Mi 4 battery (capacity 3080 mAh) soldered to the motherboard with two contacts and additionally fixed glue. Incorrect extraction can lead to short circuit or fire!
Step 1. Disconnect the battery plume
- After removing the lid, you will see a black battery plume with gold contacts.
- Carefully put a plastic mediator on it and unplug it from the circuit board connector.
Step 2: Softening the glue under the battery
There's a double-sided tape underneath the battery, so you can separate it.
- Apply a few drops of isopropyl alcohol around the edges of the battery (not on a charge!).
- Wait. 1-2 minutes - alcohol dissolves glue.
- Insert the plastic card under the battery and gently lift it, starting from the top edge.
⚠️ Warning: If the battery is swelling (seen by the bulge of the lid), do not try to remove it yourself - the risk of rupture and leakage of the electrolyte is extremely high.
Step 3: Contact check
Once the battery is removed, inspect the contact area on the board, if there is oxidation (green coating), clean it with a cotton swab dipped in alcohol, if the tracks are damaged, you will need soldering.
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If the battery is boiling and it doesn't give in, don't force it. Put your smartphone in the freezer for 10 minutes, the glue will become brittle and the battery will go away easier. But don't hold it any longer: condensate can damage the board!
Disconnection of plumes: motherboard and periphery
Once you take off the battery, you'll have access to the insides of the smartphone, and the rule here is to disconnect the plumes in the right order so that you don't tear them apart and damage the connectors.
1. Display plume
- Located at the top of the board, under a metal screen.
- Carefully lift the black lock connector (it is on the latch!) and remove the plume.
2. The camera plume
- It is located near the upper left corner of the board.
- Unscrew one screw fixing the metal plate, then remove it and disconnect the plume.
Power button/volume plume
- Thin white plume in the upper right corner.
- Put it in the mediator, but don’t pull it up – it’s short and easily torn!
4.Antenna cables
- Two black coaxial cables (Wi-Fi and Wi-Fi) GSM).
- They are removed by carefully shifting the connector sideways (not up!).
What do I do if the plume is broken?
Once all the plumes are disconnected, you can remove the motherboard, which is mounted on 6 screws (marked with the red circles in the photo below). Importantly, don't lose the small washers under the screws, they prevent the board from closing on the case!
Disassembly of the front panel: screen and buttons
If you want to replace the display or the touchscreen, you have to disassemble the front panel, which is the most difficult step, because the screen module is glued to the frame, and the buttons are fixed by fragile latches.
Step 1. Warm up the screen.
Use a hair dryer or thermoplatform (temperature) 50-60°C) to soften the adhesive around the perimeter of the display. Warm up evenly, paying special attention to the corners.
Step 2. Display separation
- Insert a plastic mediator in the gap between the screen and the frame at the Home button.
- Carefully drive the mediator around the edge, separating the glue. Do not insert deeper than 2 mm - you can damage the plume!
- If the screen fails, warm up the problem area again.
Step 3: Removing the buttons
The Home, Menu and Back buttons are attached to the latches.
- Put the Home button on the side with a thin screwdriver.
- Pull it up carefully - it will come out along with a metal frame.
- Touch buttons (Menu/Back) They're sitting on double-sided tape, and they can be separated after the hair dryer warms up.
⚠️ Warning: There's a flexible plume on the back of the Home button. If you break it, the sensor will stop working! When you install the new button, make sure the plume is not twisted.
Common Mistakes and How to Avoid Them
Even experienced craftsmen sometimes make mistakes when disassembling the Xiaomi Mi 4, and here are the most common ones and ways to prevent them:
| Mistake. | Effects of consequences | How to avoid |
|---|---|---|
| Using a metal screwdriver to slap the cover | Scratches on the case, circuit board | Use only plastic mediators |
| Overheating by a hairdryer (>70°C) | Detachment of the screen module, battery damage | Control the temperature with a thermometer |
| Application of force during battery separation | Battery rupture, electrolyte leakage | Use isopropyl alcohol to dissolve glue |
| Confused screws during assembly | Damage to board or hull | Fold the screws in order of extraction (can be on a sticky tape) |
| Forgot to disconnect the battery plume before soldering | Short circuit, failure of the power controller | Always turn off the battery first! |
Another common problem is that antenna contacts are damaged when the back cover is not removed carefully, and if you lose your Wi-Fi or mobile network after assembly, check:
- 📶 Integrity of black coaxial cables (they should sit tightly in connectors).
- 🔌 Contacts on the motherboard (are they not oxidized).
- 🛠️ Fixing of the metal frame of the cover (it serves as an antenna!).
(1) Is the battery plume connected;
(2) Are the contacts closed on the board;
3) All screws are installed correctly (especially in the processor).-->
Build a smartphone: reverse order and testing
The Xiaomi Mi 4 should be assembled in reverse order, but with a few nuances in mind:
Installation of plumes
- Start by connecting the battery plume (it should click in the connector).
- Make sure that all the plumes (display, cameras, buttons) are not twisted and sit tightly in the connectors.
2. Maternity board attachment
- Check that all screws are in place (especially under the screen module).
- Do not tighten the screws too much - you can tear the thread in the aluminum case.
Installation of the back cover
- Before gluing the lid, clean it and the body from the remnants of old glue with alcohol.
- Use a new double-sided scotch (for example, 3M 9448A) fixable.
- Press the lid evenly, starting from the center to avoid slits.
4. Testing
After assembly, turn on the smartphone and check:
- 🔋 Charging (connect the charger).
- 📞 Mobile network and Wi-Fi.
- 🎵 Speaker and microphone (call another phone).
- 📷 Camera (take a test shot).
- 👆 Touch screen (swipe your finger around all corners).
If something doesn’t work, take your smartphone apart again and check:
- Connecting the appropriate plumes.
- Contact integrity on the board.
- Correct installation of antenna cables.
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After assembly, do not turn on the smartphone immediately - let the glue under the lid grab (10-15 This will prevent dust from entering and improve leakage.