Disassembly of Xiaomi brush: from screws to mechanism - a complete guide with nuances

Xiaomi's electric toothbrushes are popular gadgets that combine affordability and technology, but even the most reliable technology breaks down: the nozzle stops rotating, doesn't hold the charge or doesn't turn on after a fall. 80% In some cases, the problem is solved by self-repair, but this requires carefully disassembling the body without damaging fragile parts. T100/T300/T500/T700, Oral-B compatible (e.g. Xiaomi Oclean X Pro).

We're not going to tell you that you need to do this, because you're here, so there's no alternative, but we're going to warn you that there's no standardized standards inside the brush. T300 The engine is mounted on the latches, and T700 — If your model is equipped with a pressure sensor (for example, Oclean). W10), disassembly without experience is fraught with sensor breakdown - its calibration requires factory equipment.

In this article you will find:

• 🔧 Step-by-step algorithm for disassembling key stages from photo (from unscrewing the bottom cover to retrieving the board).
• 🛠️ List of tools, including little-known (e.g. bearing removal device).
• ⚡ Typical breakdowns and how to diagnose them before disassembly (this will save time).
• ⚠️ Critical mistakes that lead to irreversible brush damage (and how to avoid them).

1.Preparation: security tools and measures

Before you start the screwdriver, check if the warranty period has expired (Xiaomi usually has 12 months), disassembly will void the warranty, but if the brush does not turn on or rotates in jerks, there is no choice.

• 🔩 Screwdrivers: cross-hairdriver (PH00 or PH0), flat (1.5-2 mm), torx T5 (for some).
• 🧲 Magnetic mat or bowl for screws – they are small and easily lost.
• 🔍 Lupe or magnifying glass - soldered contacts on the board are almost invisible to the naked eye.
• 🧴 Silicone lubricant (e.g, WD-40 Specialist – you will need to process gears after disassembly.
• 🔥 Hair dryer (optional) – if the body is glued, it can be carefully heated to soften the glue.

Note the battery. Xiaomi brushes use 500-800 mAh lithium-ion batteries. If the body is bloated or smells chemically, disassemble in the open air, the risk of fire is real. Also prepare a multimeter to check the voltage at the terminals (normal: 3.7-4.2 V).

⚠️ Warning: Do not use metal tweezers to retrieve the board - they can close contacts.

Removal of the bottom cover and recovery of the battery

Let's start with the simplest one: battery access. In 90% of Xiaomi models, the bottom cover is mounted on a single screw under a rubber plug. Carefully tuck the plug with a flat screwdriver or a knife (don't prick it through!). The screw is usually cross-linked, but the Oclean X Pro can have a torx. T5.

Once the screw is unscrewed, the lid will be removed with a slight effort. If it's stuck, don't pull, there may be latches inside. Walk around the perimeter with a plastic blade. Under the lid, you'll see:

• 🔋 Battery (soldered to the board or connected through a connector).
• 🔌 Charging contacts (often oxidized - they need to be cleaned with alcohol).
• 📶 Wireless charging antenna (in models with Qi support).

To remove the battery, first disconnect it from the board. at Mi Electric T300 and T500 It's soldered, so you'll need a 30-40 watt soldering iron with a thin sting. T700 And Oclean uses a connector -- just pull the black plastic lock. Don't pull the wires. They often come off at the base.

Disconnect the brush from charging for at least 12 hours|Take a picture of the location of the wires|Check the voltage with a multimeter|Put a dielectric substrate under the charge-->

Disassembly of the shell: latches vs. screws

Now the most important step is to split the body into two halves, where Xiaomi models are divided into two types:

If the case is latched, start at the top (on the nozzle side), insert a plastic blade into the slot and carefully guide along the perimeter, alternately snapping the locks. W10) There may be an additional plastic frame inside - do not confuse it with the main body!

Screw patterns are easier: unscrew all the screws (they can hide under stickers or rubber legs), then disconnect the halves.

⚠️ Attention: At Mi Electric T700 One of the screws is hidden under a metal charger contact plate, and if you don't unscrew it, the body won't go apart!

4. Extraction of the engine and the rotational mechanism

When you split the body, you'll see the heart of the brush, which is a gearbox motor, and Xiaomi's models use one of three types of motors:

• 🔄 Collector (in the old) T100/T300) — noisy.
• 🤖 Fragmentless (in) T500/T700) — quiet but moisture-sensitive.
• 🔋 Magnetic (in Oclean X Pro) – without a brush node, but difficult to diagnose.

To extract the engine:

1. Disconnect the wires from the board (they can be soldered or in the connector).
2. Unscrew 2-3 screws that fix the motor to the body.
3. Take the mechanism out carefully with the shaft. Don't pull the gears! They're often made of plastic and break.

Check gear gears for chipped or worn teeth. T300 The small gear is often erased - it can be replaced with an analogue from Oral-B (article). EB17-4). If the engine does not rotate when applying voltage, check:

• 🔌 Breaking winding (call the multimeter in resistance mode).
• 💧 Corrosion on contacts (cleaned with alcohol and cotton swab).
• 🧲 Rotor magnets – if they are unstuck, the motor will “twitch».

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Before assembly, lubricate the gears with silicone lubrication (do not use Litol or solidol - they thicken over time and block the mechanism).

5. Diagnostics of the control board

The board is the most vulnerable element. In Xiaomi, it's usually varnished, but it doesn't save you from moisture.

• 🔥 Blackened elements - a sign of overheating (often the field transistor near the motor fails).
• 💦 Oxidized tracks - green plaque or white divorces (cleaned with alcohol) + brush).
• 🔋 Bloated capacitors – in models with wireless charging (for example, T700).

To check the board, connect it to the power supply 5B (via USB-If the brush doesn't respond to the button, the problem may be:

1. Control chip (e.g., control chip, BK3631Q Oclean X).
2. Clock button – call it with a multimeter (resistance in the pressed state should be 0 Ohms).
3. Hall's sensor (responsible for rev control) at Mi Electric. T500 It's located next to the engine.

⚠️ Warning: If the board smells like a burn, don’t try to repair it without soldering experience SMD-In 70 percent of cases, it's easier to buy a new brush, and the cost of repair will exceed the cost of repair.

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In 60% of cases, the "faulty board" turns out to be oxidation of the contacts of the battery. Before replacing the board, clean the terminals with a stripe or alcohol!

6.Assembly and test after repair

Collect the brush in reverse order, but take into account the nuances:

• 🔩 Screw the screws cross-cross to avoid skewing the body.
• 🔋 Before installing the battery, check the polarity – the red wire is always on the back «+».
• 🧴 Apply a thin layer of electronic sealant (e.g., Loctite 577) to the joints of the body if the brush is operated in wet conditions.

After assembly:

1. Charge your brush for 1-2 hours (even if the indicator is 100%).
2. Check the vibration - it should be smooth, without jerks.
3. If there is a pressure sensor, calibrate it: turn on the brush, press hard on the nozzle and hold for 5 seconds.

If the brush does not turn on:

• 🔌 Check if the charging contacts are closed (a common problem after assembly).
• 🔋 Measure the battery voltage – if it is less than 3.2V, it is deeply discharged and needs a “booster” charge (use this). USB-0.5A-restricted adapter).

7. Frequent breakdowns and how to prevent them

Analysis of service centers shows that 85% of Xiaomi brush malfunctions are associated with five problems:

Xiaomi brush life, if properly operated, is 3-5 years, but even if it fails, don't throw it away. T500 Suitable for homemade projects (e.g. mini-drills), and the battery can be used in other gadgets.

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If the brush stopped turning on after falling, 90 percent of the time the problem is the wire break from the button to the board. It's the cheapest and easiest repair!

FAQ: Answers to Frequent Questions