Repair of the case for headphones Xiaomi: from diagnosis to replacement of components

Xiaomi’s wireless headphone charger case is not just a case, but a full-fledged device with a battery, power controller and charging contacts. When it stops working, many users rush to buy a new one, although in 80% of cases the malfunction can be fixed themselves. In this article, we will analyze all the typical case breakdowns from models of Redmi AirDots, Mi True Wireless Earphones, Xiaomi Buds and others, and also give step-by-step repair instructions from the simplest cleaning of contacts to battery replacement.

It is important to understand that the design of Xiaomi cases has evolved: if the early models (AirDots Basic, AirDots S) used removable batteries for 300-400 mAh, the new ones (Buds 4 Pro, Buds 5) – soldered lithium-polymer batteries with protection against recharging. This affects the complexity of repair. We will consider the universal methods that will suit most cases, and also indicate the key differences for specific models.

Typical malfunctions of Xiaomi cases and their signs

Before you can analyze the case, you need to pinpoint the problem, and here are the most common symptoms and their possible causes:

• 🔋 Case not charged from cable - damaged USB-port, contacts oxidized, charging controller or battery itself is faulty.
• 🔌 Headphones are not charged in the case - contaminated or deformed spring contacts, break the chain inside the case, failure of the controller.
• 💡 The indicator does not burn or flashes abnormally - a problem with the control board, short circuit, battery discharge below a critical level.
• 🔥 Case warms or swells - critical battery failure, requires immediate shutdown and replacement!
• 📵 Not detected by computer/charger - damage USB-power-connector.

If the case is swelled or deformed, its continued use is dangerous - lithium-ion batteries in this state can ignite, in which case the only way out is a complete replacement of the battery with a check of the charging circuit.

Tools and materials for repair

For disassembly and repair of the case you will need:

• 🔧 Plastic mediators or shoulder blades - for neat opening of the body (metal tools can leave scratches).
• 🔨 Thin screwdriver (cross, 1-1.5 mm) - for unscrewing screws (in some models used Y00 or T3).
• 🧲 Magnetic substrate or cup – to avoid losing small details.
• 🧴 Isopropyl alcohol (90%+) — cleaning contacts and boards.
• 🔋 New battery (if you need to replace) – select the case model (for example, AirDots S suitable battery). 3.7V 400mAh plug-in JST 1.25mm).
• 🔥 A soldering iron with a thin sting (0.5-1 mm) and solder - for repairing cliffs or replacing components.

For models with adhesive attachment (such as Xiaomi Buds 4) may require a hair dryer or a thermo-air station to soften the adhesive.Be careful: overheating can damage the battery!

⚠️ Note: If you have never soldered chips, do not try to repair the charging controller yourself.

Disassembly of the case: step-by-step instructions

The disassembly algorithm varies by model, but the general principle is the same. Let's take a generic method like Redmi AirDots S:

1. Then, put the back on the back, and then you can put the back on the back.
2. Carefully put a plastic mediator under the bottom of the case (where USB-There's usually a little gap there.
3. Swipe the mediator around the perimeter, gradually snapping the mounts. Don't force it, the plastic is fragile!
4. If the lid does not lend itself, warm up the dryer of the edge of the case (temperature ~ 60 ° C) - this will soften the glue.
5. After removing the lid, disconnect the battery plume (if it is removable) or unwrap the wires (if soldered).

In Xiaomi Buds 3/4 models, the screws can be hidden under rubber plugs (like under the legs of a case).

No debris inside the enclosure |

Contact integrity for headphones |

Proper battery connection |

Securing all screws and latches-->

⚠️ Note: In cases with wireless charging (for example, Mi True Wireless Earphones) 2S) And under the top cover is an induction coil. Don't touch it with metal tools, it could damage the chain!

Cleaning and repairing contacts for headphones

If the case is being charged from the cable, but the headphones are not charging inside, the problem is probably the spring contacts, they become oxidized or deformed over time.

1. Wet the cotton swab in isopropyl alcohol and clean the contacts on the case and headphones. For hard-to-reach places, use a toothpick.
2. If the contacts are bent, bend them carefully with tweezers. Be careful - they are fragile!
3. For reliability, you can coat the contacts with a thin layer of technical Vaseline (not silicone lubricant!).
4. If the spring breaks, it can be replaced with a similar one from the donor case or use conductive glue (for example, Contac Cafe).

In Xiaomi Buds 4 Pro models, the contacts are often soldered to the board. If they come off, you will need a soldering iron with a thin sting and solder with flux. The soldering temperature should not exceed 300 ° C, so as not to damage the board.

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If your headphones still don't charge after cleaning your contacts, check them on another case (from a friend or in the service), perhaps the problem is with the headphones themselves, not the charger.

Replacement of the battery in the case Xiaomi

If the case is not holding a charge or not turning on at all, the battery is likely to fail. In the Redmi AirDots and Mi True Wireless Earphones 2 models, it can be replaced yourself:

1. Buy a new battery with the same parameters (voltage, capacity, connector). AirDots S will fit 3.7V 400mAh with a JST 1.25mm connector.
2. Solder off the old battery, polarize. Use solder suction or swab to clear the contact areas.
3. Salt a new battery, making sure that the plus (+) and minus (−) are connected correctly. Short circuit will cause the board to fail!
4. Secure the battery with bilateral tape (in the original used thermal glue).

In cases Xiaomi Buds 3/4 battery is often glued to the case. To remove it, warm up the bottom of the case with a hairdryer (do not direct hot air to the board!). After replacing the battery, check its operation with a multimeter - the voltage should be in the range of 3.7-4.2V.

Repairs USB-port and charger

If the case is not charged from the cable, but the indicator reacts to the connection (blinks or glows), the problem may be in the USB-The port or the power controller:

• 🔍 Visual port inspection - often contacts inside a Micro-USB or Type-C connector become contaminated or warped.
• 🔧 Checking soldered contacts - if the port is wobbly, it needs to be soldered. Xiaomi cases often use connectors with 5 contacts (VBUS, GND, D+, D-, CC).
• 💻 Diagnostics of the controller – if the port is serviceable, but charging is not going, the problem is in the chip (usually marking begins with a BQ, TP4056 or SY6970). Replacing her requires rationing experience. SMD-component.

In cases with Type-C (for example, Xiaomi Buds 4), the 5.1k resistor on the CC line often fails. It can be replaced, but this requires a microscope and a soldering station with temperature control.

⚠️ Note: If after the repair USB-If the port case is starting to warm or not turning on, immediately disconnect it from charging.

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In 60% of cases, “non-working" USB-The port can be rebuilt by simply cleaning the contacts.

Wireless charging problems (for supported models)

Cases Mi True Wireless Earphones 2S, Xiaomi Buds 3 Pro and later support wireless charging according to the Qi standard.

1. Check whether the case is responding to the charging station - the indicator should light up.
2. Clean the induction coil (located under the top cover) of dust and metal particles.
3. Make sure the charging station is producing enough power (minimum 5W).
4. If the coil is damaged (a break or short circuit), it can be replaced, but this requires soldering 4-6 contacts.

In some cases, the problem lies in the wireless charging controller (IDT P9221 or similar), which can only be replaced at the service center.

FAQ: Frequent questions about repairing Xiaomi cases