Disassembly of smart scales Xiaomi Mi Smart Scale 2: detailed instructions with photos and tips

Xiaomi Mi Smart Scale 2 is a popular weight and body composition control device, but even these are not immune to breakdowns. Most often, users are faced with the need to disassemble the scales to replace the battery, repair sensors or clean contacts. However, the device’s design does not involve easy access to the insides: the manufacturer did not provide service hatches or removable covers.

In this article, you will find step-by-step instructions for disassembling photos of key steps, a list of necessary tools and unique tips for preventing damage to fragile elements (for example, a touchpad or a circuit board), we will also analyze the typical errors that lead to the failure of the scales after self-repair, and give recommendations for reverse assembly.

Warning: disassembling the Mi Smart Scale 2 requires care and patience. If you are not sure about your skills, you should contact the service center. But if you decide to act on your own, follow our recommendations to avoid annoying mistakes.

Preparation for disassembly: tools and security measures

Before you start disassembling, make sure you have everything you need, and the wrong tools are the main cause of damage to the body or internal components.

• 🔧 Plastic mediator or opener (to gently disconnect the latch of the case). Metal tools can leave scratches!
• ⚙️ Screwdriver kit: cross-haired (PH00) and flat (1.5-2 mm) for screws inside the device.
• 🔋 Thin-ended tweezers – for working with small details and battery contacts.
• 📸 Smartphone or camera – take pictures of each stage of disassembly so as not to confuse the details during assembly.
• 🧲 Magnetic mat or screw storage container (they are easily lost!).

Also, prepare your workspace: clean, well-lit, and without static electricity (ideally an antistatic mat) and avoid disassembly on carpets or soft surfaces, as lost screws will be difficult to find.

⚠️ Warning: Do not disassemble the scales of the Mi Smart Scale 2 in humidity above 60% or in a dusty room. Getting moisture or dust particles on the touch panel or contacts can lead to incorrect operation of the sensors after assembly.

Step 1: Remove the top touchpad

The most critical step is to separate the glass panel from the body, and it's attached to double-sided tape and plastic latches that are easy to break when handled carelessly.

1. Put the scales on the soft fabric with glass down, which will protect the panel from scratches.
2. Insert a plastic mediator into the gap between the glass and the body at one of the corners. Carefully drive the tool along the perimeter, gradually separating the panel. Do not apply force - if the tape does not respond, slightly heat it with a hairdryer (temperature no higher than 50 ° C).
3. When the panel is separated, put it in a safe place. Don't touch the inside of the glass, because it has a conductive coating that's easy to damage.

Under the glass, you'll see 4 screws (in the corners) and a plume connecting the touchpad to the board. Don't pull the plume - it needs to be gently disconnected later!

💡

If the tape is too sticky, use a thread or dental floss: sniff it under the glass and "saw" back and forth until the glue weakens.

Step 2: Unconnecting the plume and removing the fee

Now you have to turn off the touchpad plume and remove the main board, and the key is not to damage the contacts or confuse the order of action.

1. Unscrew the 4 screws with the PH00 cross screwdriver, and put them in a magnetic container to avoid losing them.
2. Carefully tuck in the plastic latch that holds the plume (it's white and located next to the connector). Use tweezers or nails.
3. Remove the plume from the connector by pulling it perpendicular to the board. Don't pull it sideways, it could tear the contacts off!
4. Now you can take the board off. It's attached to 2-3 small screws (depending on the revision of the device), and you can put it on an antistatic surface.

On the board, you'll see:

• 🔋 Battery connector (red and black wires).
• 📶 Bluetooth antenna (thin metal track).
• 🛠️ Sensor chip (usually closed with metal screen).

All 4 screws of the body unscrewed

Sensor plume disconnected from connector

The fee does not apply to metal objects

Photograph of the location of the details taken-->

Step 3: Replace the battery (battery)

Most commonly, the Mi Smart Scale 2 is disassembled to replace the battery, using a 500-600mAh lithium-ion battery of the type 18650 (depending on the revision).

1. Disconnect the battery connector from the board. Use tweezers to gently pull the black wire.
2. Remove the battery from the holder. It can be glued to double-sided tape -- put it in a plastic mediator.
3. Install a new battery 18650 with similar parameters. The polarity should match (plus to plus, minus to minus).
4. Connect the connector back to the board. Make sure the contacts are not bent.

If the scales are not turned on after the battery is replaced, check:

• 🔌 Correct connection of the connector (sometimes it is not fully inserted).
• 🔋 The voltage of the new battery (should be 3.7-4.2 V).
• 🛠️ Integrity of the fuse on the board (a small black component next to the connector).

⚠️ Warning: Don't use batteries from other devices, even if they look similar. The battery in the Mi Smart Scale 2 has overcharging protection, and cheap analogues may not support it, which will lead to a fire!

Step 4: Diagnostics and repair of sensors

If the scales are not properly weighted or turned on, the problem may lie in the strain gauges (they convert mechanical pressure into an electrical signal), which require special care to be checked and replaced:

First, look at the sensors visually:

• 🔍 Integrity of wires – they should not be clamped or oxidized.
• 🧲 Mounting sensors to the board - check the soldering (if you have skills).
• 📏 Location – sensors should be symmetrically placed in corners.

To test the sensors, you will need a multimeter:

1. Transfer the multimeter to resistance measurement mode (200 Ω).
2. Connect the probes to the sensor contacts, and a valid strain gauge will show resistance of 300-500 Ohms.
3. If the resistance is near zero or infinity, the sensor is defective and needs to be replaced.

It's hard to replace the sensor on your own -- they're soldered to the board. SMD-But you can try to clean the contacts with alcohol and a soft brush if the problem is oxidation.

Step 5: Cleaning contacts and internal surfaces

Dust, sweat, or moisture can disrupt the balance, and regular cleaning of the internal components will prolong the life of the device.

• 🧹 Touch panel: wipe the inside of the glass with a wiltless napkin dipped in isopropyl alcohol (70% or higher). Don't use paper towels - they scratch!
• 🔌 Battery and connector contacts: clean with a cotton swab dipped in alcohol. Use an eraser for oxidized contacts (carefully!).
• 🛠️ Fee: blow with compressed air (canister) or soft brush. Don't touch chips!

After cleaning, allow the parts to dry completely (at least 30 minutes). Do not dry with a hair dryer - this can damage thermosensitive components.

If the scales have been exposed to moisture (for example, have been poured), they need to be disassembled and dried for at least 24 hours in a dry place. Sometimes it helps to put the board in a bag of silica gel (it absorbs moisture).

💡

Cleaning with alcohol removes not only dirt, but also residues of flux after soldering, which improves contact and prevents corrosion.

Step 6: Reverse Assembly and Testing

The Mi Smart Scale 2 should be assembled in reverse order, but with a few nuances in mind:

1. Make sure all plumes and connectors are tightly connected. Check the battery polarity again!
2. Stick the glass panel onto a new two-way Scotch (you can use Scotch for smartphones 0.5-1 mm thick). Remove the old Scotch with the residues of alcohol.
3. Twirl the screws cross-cross to avoid skewing the body.
4. Turn the scales on and check them. If they don't turn on, take them apart again and check the contacts.

After assembly, perform the test:

• 📱 Connect the scales to the Mi Fit app and check the data synchronization.

⚠️ Note: If after the assembly of the scales show an error E1 or E2, This means a sensor or board problem. Take the device apart again and check the integrity of the plumes and contacts. E3 usually associated with a battery (incorrect polarity or low voltage).

FAQ: Frequent questions about the Xiaomi Mi Smart Scale 2 disassembly