Step-by-step disassembly of the electric screwdriver Xiaomi: from the battery to the engine

Xiaomi screwdrivers are popular compact tools that combine convenience and functionality. However, even the most reliable equipment can fail: stop holding the charge, there are extraneous noises or the screwdriver refuses to turn on. In most cases, the problem is solved by self-repair, but you need to know how to properly disassemble the device without damaging its fragile components.

In this article, we will discuss in detail the process of disassembling the Xiaomi electric screwdriver (on the example of the Mijia Electric Screwdriver and Xiaomi Wowstick models), specify the necessary tools, warn against typical errors and give recommendations for diagnosing malfunctions. If you have never repaired power tools before, do not worry - our instructions are adapted for beginners.

Important: disassembling the tool will void the manufacturer's warranty if it is still valid. Make sure you're ready for this step before you start.

Preparation for disassembly: tools and security measures

Before you start dismantling, prepare the workplace and the necessary tools, which will not only speed up the process, but also minimize the risk of damage to parts or injuries.

Minimum set of tools for disassembling Xiaomi screwdriver:

• 🔧 Set of screwdrivers (cross-haired) PH00, flat 2.0 mm, hexagon 1.5 mm)
• 🔨 Plastic mediators or shoulder blades for opening the body
• 🧲 Magnetic mat or tray for fasteners (so as not to lose small screws)
• 🔍 Loop or magnifying glass (for inspection of small details)
• 📸 Smartphone for photographing the dismantling stages (useful when reassembling)

We also recommend using an antistatic bracelet if you plan to work with control boards. Static electricity can damage sensitive chips.

⚠️ Warning: Do not disassemble the screwdriver if it was recently in operation. Let the battery cool for 30 to 60 minutes - this will reduce the risk of short circuits in accidental contact with the current-carrying parts.

If you're disassembling a battery replacement tool, buy a compatible battery in advance. Xiaomi Mijia models will suit the type 18650 voltage batteries. 3.7V and a capacity of at least 2000 mAh. Wowstick may require specialized batteries with a connector JST 2.0.

Disassembly of the body: remove the upper and lower covers

Xiaomi's screwdriver body consists of two halves held together by screws and latches. Let's start by removing the visible fastener.

Step 1: Removing screws

• 🔍 Check the case for screws. Usually 4-6 of them: 2-3 under rubber legs (if any) and 2-3 under stickers.
• 🧹 Carefully remove stickers and rubber inserts with a plastic shoulder blade.
• 🔧 Unscrew all the screws using the right screwdriver.Wooofstick models may have torx-bit screws. T5.

Step 2: Separating the halves of the body

After removing the screws, insert the plastic mediator into the gap between the halves of the case (usually near the battery compartment) and carefully spread them.

If the case fails, don't use excessive force. You may have missed a hidden screw or latch. In Mijia models, an extra screw may be under the on button, so you need to gently tuck it in and remove it.

⚠️ Attention: In some versions of Wowstick, the top cover is connected to the bottom thin plume that goes to the control button. Don't pull the lid sharply - first disconnect the plume!

Removal of the battery: features and precautions

The battery is one of the most vulnerable parts of the screwdriver, and swelling, leaking electrolytes, or loss of capacity are common causes of failure, so let's look at how to properly remove the battery.

Types of battery attachment in Xiaomi:

Step-by-step extraction instructions:

1. Disconnect the battery plume from the control board (if it is connected through the connector).
2. If the battery is soldered, carefully solder off the contacts using a soldering iron with a power of no more than 30 W.
3. Remove duct tape or heat-glue with a plastic shoulder blade or hair dryer (heat to 60–80)°C).
4. Remove the battery, avoiding deformation or punctures.

If the battery is swelling, do not try to pierce or bend it, this can lead to fire.

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Before you change the battery, check the voltage with a multimeter. 2.5V, The battery is deeply discharged and may not recover even after replacement.

Diagnostics and disassembly of the engine

If the screwdriver doesn't rotate the bit or makes uncharacteristic sounds (screaming, vibration), the problem may lie in the electric motor or gearbox, and we'll figure out how to check and dismantle these knots if necessary.

Signs of engine failure:

• 🔊 Extraneous noise during operation (may indicate wear of brushes or bearings).
• 🔥 Overheating of the body in the motor area (indicates an interturn circuit).
• 🔄 Uneven rotation or jerking (problems with winding or gearbox).

How to disassemble the engine:

1. Disconnect the control board from the engine by unfurling or disconnecting the contacts.
2. Unscrew the screws that hold the engine in the body (usually 2-3 screws from the end).
3. Remove the engine with the gearbox. In Wowstick models, the gearbox can be integrated into one unit.
4. To disassemble the gearbox, remove the locking ring with the help of round-cutters and carefully remove the gears.

Examine the engine brushes (if any) - they are more than 50% wear and tear require replacement. Also check the integrity of the winding: blackening or the smell of burns indicates a short circuit.

If the engine is faulty, it is easier to replace it whole than repair it. The original Xiaomi engines can be found on AliExpress or in service centers by the articles listed on the device body.

Management fee: inspection and repair

The control board is responsible for adjusting speed, rotational direction and overload protection, and its failure can manifest itself in the form of a lack of response to a button, spontaneous on or unstable operation.

Typical board problems:

• 🔥 Burnt resistors or transistors (blackened elements are visible).
• 💧 Oxidation of contacts (especially if the screwdriver was operated in wet conditions).
• 🔌Cold soldering (unreliable soldering compounds that can crack over time).

Diagnostics of boards:

1. Look carefully at the board under the magnifying glass, look for burn marks, swollen capacitors or cracks in the tracks.
2. Call the multimeter of the power chain (from the battery to the driver chip).
3. Check the operability of the power button by measuring the resistance in the pressed and pressed state.

If you find burned items, but do not have experience soldering SMD-Replacement of chips requires specialized equipment (sweeping station, flux, solder with low melting point).

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The most common cause of failure of the control board is overcurrent, which occurs when a bit is jammed or prolonged operation at maximum power. Always use the screwdriver according to its specifications!

Assembly of electric screwdriver after repair

Once the fault has been fixed, you need to properly assemble the device to avoid further breakdowns.

Assembly order:

1. Set the control board in place and connect all connectors (battery, engine, button).
2. Secure the motor and gearbox, making sure the gears match.
3. Place the battery in the compartment and fix it (screws, duct tape or thermal glue).
4. Combine the halves of the body, starting with the battery area, and gently snap them.
5. Twisting all screws without putting excessive effort (the risk of tearing the thread).

Post-assembly check:

• 🔋 Connect the screwdriver to the charger and make sure the charge indicator is working.
• 🔄 Test the rotation in both directions at minimum and maximum speeds.
• 🔊 Listen, there's no extraneous noise or vibration.

If after assembly the screwdriver works incorrectly, disassemble it again and check:

• Correct connection of all connectors.
• No gaps between gears of the gearbox.
• Integrity of soldered joints on the board.

Frequent mistakes in disassembly and how to avoid them

Even experienced craftsmen sometimes make mistakes that lead to additional breakdowns, and here are the most common ones and ways to prevent them:

Another common mistake is ignoring the inspection of parts after disassembly, for example, many people forget to clean the gearbox of old lubrication or check the backlash of the engine bearings, which leads to the fact that after assembly the problem remains unresolved.

If you are not sure of your abilities, it is better to contact a service center. For example, in Moscow and St. Petersburg there are specialized workshops for repairing Xiaomi power tools, where disassembly and diagnostics will cost 500-1500 rubles.

FAQ: Frequent questions about the dismantling of the electric screwdriver Xiaomi