Modern personal care gadgets, such as Xiaomi’s electric trimmers, often require maintenance that is not provided by standard user instructions. Owners of the popular Mijia Electric Hair Clipper face the need to deep-clean or replace the knife unit when the device stops coping with hair or begins to get stuck. Disassembling this device is a delicate process that requires understanding the design and the presence of specific tools.
Unlike conventional machines, it uses a hidden fastener and a tight assembly to provide moisture protection, and trying to open the case without preparation can cause plastic latches to break or damage the battery, and our goal is to describe in detail the algorithm of actions that will allow you to safely access the internal components of the device.
Before you start taking action, you need to realize that any interference with the design of the device will void the official warranty. However, if the life of the knives is exhausted or the mechanism requires lubrication, you simply have no choice.
Tools and workplace preparation required
The success of the operation depends on 90% of the correctly selected tools. Xiaomi Mijia design does not involve the use of standard screwdrivers from a household kit. You will need a set of precision tools, including slash and cross bits of small diameter, as well as thin plastic mediators to open the case.
Special attention should be paid to the organization of the workspace. Small screws are easily lost, and the entangled parts can lead to the inability to reverse assemble.
You will need to work:
- 🔧 Phillips screwdriver set #00 and flat silk 1.5 mm
- 🧤 Thin plastic blades (poodgers) for opening
- 💧 Isopropyl alcohol and lilac-free wipes
- 🛢️ Special oil for lubricating knife pairs
It is important to prepare a place in advance where nothing will distract you from the process. Static electricity can damage electronics, so it is advisable to work at a table with antistatic coating or just periodically touch grounded metal objects.
⚠️ Warning: Never use metal knives or needles to tweak plastic parts of the case - this is guaranteed to leave traces and can damage the internal wiring.
☑️ Preparation for trimmer disassembly
Dismantling of the external knife block and protective cover
The first step is always to remove the removable elements. In the Mijia Hair Clipper, the knife unit is not only attached to the latches, but also fixed by screws hidden under decorative linings. Carefully remove the limiter comb if it is installed.
Then you take the cutting knot off, and in some versions, it's held on two small screws under the knife head, and if you don't have the screws, the unit is removed by force, but you have to be very careful not to break the plastic rails, and you have to push the edge of the block with a thin tool.
Once the knife is removed, you'll have access to the drive mechanism, and here you'll see the eccentric motor and the return spring, and it's in this node that the hair and skin fat that most often accumulate, and over time, they become a solid mass that blocks movement.
Deep cleaning often requires removing the bottom cover covering the battery compartment, which can be mounted on screws at the bottom of the body or held on tight latches around the perimeter, and proceed consistently by checking for hidden fasteners under rubber plugs.
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Before removing the knife unit, take a photo of its position with the device on (if possible) or remember the orientation so that the direction of the blades does not confuse when assembled.
Opening of the main body and access to electronics
The most difficult step is to separate the main body. Xiaomi's build logic often relies on using hidden screws under stickers or in the recesses. Carefully inspect the bottom end of the device and the area around the power button.
If there are no visible screws, the body is probably assembled on the latches. Walk the plastic blade around the perimeter of the seam. You will hear the characteristic clicks when the locks are unbuttoned. Don't use excessive force: if the part does not open, you missed the fastener.
Inside the case, there's a circuit board with a charge controller and motor control, and there's a lithium-ion battery, and be very careful with the plumes and wires that go to the circuit board, which are very thin and easily break when you squirm.
Often, the board is attached to additional screws, and once they are unscrewed, the module can be removed for inspection, and note the condition of the contacts and the presence of oxides that may have formed due to moisture.
| Component | Type of attachment | Risk of damage | Tool. |
|---|---|---|---|
| Knife block | Screws + Latches | Slice pottery | Screwdriver #00 |
| Body cover | Plastic clips | Plastic cracks | Mediator. |
| Management fee | Screws + plume | Contact break | Tweezers |
| Battery | Glue base | Puncture of the hull | Plastic spatula |
Battery replacement and motor maintenance
If the machine stopped holding the charge, the battery most likely failed. Xiaomi Mijia uses standard 14500 elements or specific batteries with brazing pins. Replacing requires skills with a soldering iron, since contacts are often welded with spot welding.
The motor in these devices is usually mounted on rubber dampers to reduce vibration. It's important to not lose these rubber rings when disassembling. The motor itself rarely fails, more often the problem is contamination of the shaft or drying out the lubricant in the slip bearings.
Use isopropyl alcohol to clean the old lubricant and dust to maintain the engine. After the alcohol is dry, apply a drop of special synthetic oil. Do not use WD-40 or engine oil - they are too liquid or, conversely, too thick for high revs.
⚠️ Warning: When soldering a new battery, do not overheat the contacts so as not to damage the internal structure of the battery or cause it to ignite.
The assembly of the motor assembly must be polarized; the entangled polarity on first turn on can instantly disable the control board; check the connection three times before power is applied.
Cleaning and lubrication of the knife mechanism
Back to the most important element, the knives, the ceramic top knife and the metal bottom knife require special care, and if you disassemble the machine because of bad haircut, you may have broken the geometry of the clip or chipped on the ceramics.
Carefully remove all hair from under the knives. Use a small brush. After mechanical cleaning, wipe the surface with alcohol. Lubrication is applied only to the metal parts of the lower knife and the points of friction.
The ceramics don't need to be lubricated, they work in tandem with the metal by slipping, and the excess oil on the ceramics will only cause it to splash out when it's working and stain your hair.
How to check the sharpness of knives at home?
Device assembly and final testing
The assembly process is reversed, but with one important thing: you need to snap the case before you install the screws. Make sure all the plumes are in their channels and not clamped. Any tension of the wires is unacceptable.
Write the screws evenly, without fanaticism. Xiaomi plastic is pretty good, but the thread in it can break when you pull. After closing the case, check the on button and charge indication.
Turn on the device without the knife unit installed (for a few seconds) to make sure the engine is working. The characteristic sound should be smooth, without any foreign knocks or screeching. If everything is okay, install the knife and do a test run.
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The main secret of long-term trimmer service is regular hair cleaning after each use and lubrication once a month, which eliminates the need for complex disassembly in the future.