Xiaomi Mi 4 is a legendary smartphone released in 2014, which is still used by many users. Over time, even the most reliable equipment requires repairs: whether it is battery replacement, dust cleaning, repair connectors or fault diagnosis. Disassembly Mi 4 has its own features due to the non-shattered body, glue mount and fragile plumes. In this article, you will find a step-by-step photo instruction, a list of necessary tools, as well as unique tips for preventing damage to the board and display, which are not found in the standard guides.
Before you start, consider that disassembling a Xiaomi smartphone will void the warranty (if it is still valid) and can lead to irreversible damage if you do not act correctly. For example, overheating the hair dryer when peeling off the back cover often causes detachment of the sensor or damage to the battery. We will tell you how to avoid such errors and conduct disassembly as safely as possible.
If your goal is to replace the battery, clean the speakers or repair the camera, this guide is perfect. For complex tasks (such as soldering chips) you will need additional skills and equipment. At the end of the article you will find an FAQ with answers to frequent questions and a list of typical Mi 4 breakdowns that can be fixed yourself.
Preparation for disassembly: tools and security measures
Before you disassemble the Xiaomi Mi 4, prepare the workspace and tools. Lack of lighting or lack of magnetic propeller support are common causes of loss of parts or damage to plumes.
- 🔧 Set of screwdrivers (cross-haired) PH00, flat 1.5 mm, five-pointed T5 for some).
- 🔥 Dryer or thermo-air station (power not higher than 300 W, temperature up to 80)°C).
- 🧲 Magnetic mat or tray for screws (so as not to confuse them when assembly).
- 📏 Plastic mediators (2-3 (p) to separate the cover without scratching.
- 🔋 Suction (diameter) 3-4 cm) to lift the display unit.
- 🧴 Isopropyl alcohol (90%+) Cleaning contacts and removing glue residues.
- 🔍 loope USB-microscope (optional, to check soldering).
Important: do not use metal tools to separate the cover - they leave microcracks on the aluminum body of the Mi 4. Also avoid overheating: if the temperature of the hair dryer exceeds 90 ° C, the glue will melt too quickly and you risk damaging the plumes of the display or battery. To monitor the temperature, you can use an infrared thermometer (costs inexpensive, but saves from overheating).
⚠️ Note: If the Xiaomi Mi battery 4 If you're swelling, don't disassemble your smartphone without protection, then blown-up cells can ignite when punctured. 0% (If possible, then place your phone in the freezer. 1-2 You'll be able to use gloves and goggles to reduce the risk of fire.
Step 1: Removing the back cover - how not to damage the body
The back of the Mi 4 is attached to the glue and latches around the perimeter, and the main difficulty is the uneven distribution of the glue: there is more glue in the upper part (near the camera) than in the lower part, and if you pull the lid without preheating, it can crack or bend the frame.
Instructions for removal:
- Turn off your smartphone and remove the tray for SIM-cards (use a paper clip or special key).
- Heat the hair dryer back cover around the perimeter for 2-3 minutes, keeping it at a distance of 5-7 cm Temperature - no higher than 80 ° C.
- Insert a plastic mediator into the gap between the lid and the body at the charging socket, and carefully steer it along the edge until you hear the snaps of the latches.
- When the lid begins to move away, do not pull it sharply - antenna plumes and NFC pass under it (if they are in your modification).
If the lid doesn't lend itself, don't increase the temperature of the hair dryer -- you better repeat the heat again. If you get too hot, the glue can drain onto the board, which you'll have to clean with alcohol. Also, pay attention to the sealing gum around the chamber, which is easily damaged by a mediator.
☑️ Check before removing the lid
| Typical mistake | Effects of consequences | How to avoid |
|---|---|---|
| Use of a metal tool | Scratches on the body, damage to antenna tracks | Use only plastic mediators |
| Overheating by a hairdryer (>90°C) | Sensor detachment, battery damage | Control the temperature with a thermometer |
| Sharp compartment of the lid | Breaking antenna plumes or NFC | Separate the cover slowly, starting at the bottom edge |
| Getting glue on board | Short circuit, corrosion of contacts | Remove excess glue with alcohol immediately after removing the lid |
Step 2: Shutting down the battery – why it’s critical
When you remove the lid, the first thing you do is turn off the battery. In the Xiaomi Mi 4, it's connected via a JST 1.0 connector with black and red wires. Even if the phone is turned off, the board stays on — if you accidentally close the tool, you can burn the power controller.
How to turn off the battery:
- Find the battery connector on the board (usually located at the bottom, next to the charging connector).
- Carefully tuck the connector with a plastic spatula, pulling it up. Don't use metal tools - you can close contacts.
- After disconnecting, check the voltage on the board contacts with a multimeter (should be 0 V).
If the connector is "stopped" and does not go away, do not apply force. Moisten it with isopropyl alcohol and wait 1-2 minutes - this will help dissolve the oxides. In extreme cases, you can slightly heat the connector with a hair dryer (temperature is not higher than 60 ° C), but do not direct the air flow to the battery!
⚠️ Warning: If the battery is swelling, don't try to turn it off - the risk of short circuit is too high, in this case it is better to immediately remove it completely, after draining the phone to 0% and cooling the battery in the freezer.
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If the battery is turned off after the phone is still turned on when you press the power button, then there is power left somewhere (for example, from capacitors), in which case wait 5-10 minutes before continuing work.
Step 3: Removing the motherboard - working with plumes and screws
The Mi 4 board is mounted on 12 screws of different sizes: 8 cross (PH00) and 4 five-beam (T5). Don't confuse them when assembled - the screws under the antennas are shorter than those that attach the board to the body.
- 📞 The plume of the display module (located under a metal cover, mounted on latches).
- 🔊 The plumes of the speakers (upper and lower, attached to the glue).
- 📷 Main camera plume (thin, easily torn with careless movement).
- 🎤 Microphone plume (attached to bilateral scotch).
Procedure:
- Take a picture of the location of the screws (you can use the phone) - this will help not to confuse them when assembling.
- Unscrew all the screws and fold them on a magnetic mat in order of extraction.
- Carefully tuck the board with a plastic blade from the bottom edge. Don't pull it sharply - the trains of the Home button and the vibrator pass under the board.
- If the fee is not going, check if all screws are unscrewed (often forget about the screw under the NFC sticker).
When removing the board, be especially careful with the charging connector - it is soldered to the board and can come off with excessive force. If the connector wobbles, it is better to immediately re-silver it, otherwise it will fall off completely over time.
What to do if the screw "slipped"
Step 4: Disassemble the display module – when replacement is required
The display Xiaomi Mi 4 consists of three layers: touch glass, digitizer (touchscreen) and LCD-In 90% of cases, only glass cracks, but sometimes the matrix is damaged (vertical stripes or broken pixels appear), replacing the glass separately from the matrix is possible, but requires special glue and press.
If you decide to replace the display completely, follow this instruction:
- Heat the front panel with a hair dryer to 70°C (direct airflow to the edges, not the center).
- With a suction cup, lift the display from the bottom edge. If it doesn't respond, repeat the heat.
- Insert plastic mediators under the glass and carefully guide them around the perimeter, separating the glue.
- When the display is separated, disconnect the plumes: the main (20-pin) and the home button (4-pin).
Important: Do not use a knife or metal blades to separate the display - they can damage the plumes under the glass. If the glue is too strong, moisten it with alcohol and wait 1-2 minutes. Also pay attention to the metal frame around the display - it often remains on the board and can interfere with the installation of a new module.
| Symptoms. | Probable cause | Should the display be changed? |
|---|---|---|
| There are cracks on the glass, but the image is | Only the glass is damaged. | You can replace the glass separately (difficult) |
| Vertical stripes on the screen | Damaged. LCD-matrix | Replacement of the entire display module is required |
| Touchscreen doesn't respond to touch | Damaged digitizer or plume | Display replacement or plume repair |
| Screen flickering, artifacts | Problems with a graphics chip or plume | Diagnostics of the board, replacement of the plume |
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If colored stripes or uneven lighting appear after replacing the display, check the density of the plumes. Often the problem is solved by reconnecting the connectors.
Step 5: Replace the battery – the choice of analogue and the nuances of the installation
The Xiaomi Mi 4 battery has a capacity of 3080 mAh and is attached to double-sided tape. Over time, it loses capacity, swells up or stops holding charge. When replacing, it is important to choose a quality analogue - cheap batteries often have an understated real capacity (for example, instead of 3080 mAh - 2200 mAh).
Recommended replacement manufacturers:
- 🔋 ZOP Power (full analogue of the original, capacity 3080 mAh).
- 🔋 CAMELION (Good price/quality ratio, capacity of 3100 mAh).
- 🔋 Baseus (premium segment, capacity 3200 mAh, but more expensive).
Instructions for replacement:
- Unplug the old battery with a plastic spatula. If it swells, be careful not to puncture it!
- Clean the seat of the glue residue with alcohol, check if there are any traces of corrosion (green plaque) on the board.
- Remove the protective film from the new battery and glue it to double-sided tape (comes with the kit).
- Connect the battery connector to the board. Before assembly, check the voltage with a multimeter (should be ~3.7-4.2 V).
⚠️ Warning: If the battery is not turned on after the battery is replaced, check the fuse on the board (located next to the charging connector). It can burn if the battery is short-circuited.
Typical Xiaomi Mi 4 breakdowns and whether they can be fixed independently
Xiaomi Mi 4 is a reliable smartphone, but it also has weaknesses.
- 🔌 Charging does not work: Cause: oxidation of the connector, a plume break, failure of the power controller. Repair: cleaning the connector with alcohol, replacing the plume or soldering of the controller (difficult to do).
- 📶 No network or weak signal: Cause: damage to antenna tracks, antenna connector dump. Repair: soldering connector or replacement of antenna module.
- 🔊 The speaker or microphone is not working: Cause: contact oxidation, plume break, speaker failure. Repair: speaker or plume replacement (just), contact cleaning.
- 📷 Camera fails to focus or gives out error: Cause: contamination of module, plume break, camera failure Repair: cleaning of lenses, replacement of plume or camera module.
- 🔋 Battery goes down quickly: Reason: battery wear, high power consumption due to software errors. Repair: battery replacement, resetting or flashing.
If you are not sure of your skills, some breakdowns (for example, soldering of a power controller or replacing a graphics chip) are better entrusted to professionals. The cost of repairing the Mi 4 in service centers usually does not exceed 3-5 thousand rubles, which is cheaper than buying a new smartphone.