Why Mi Band 3's Disassembly Needs Caution
The Xiaomi Mi Band 3 fitness bracelet, released in 2018, is still popular with users due to its reliability and functionality. However, over time, even this device can require repair: a discharged battery, a cracked display or contaminated charging contacts make owners think about disassembling. Unlike smartphones, it is difficult to disassemble the Mi Band 3 without damage - the manufacturer has not provided service hatches, and the body is sealed.
In this article, you will find detailed photo instructions, tools and unique tips to minimize risks (such as how to avoid damaging the display plume when you open the wristband), and we will also look at common errors that cause the bracelet to break, and alternative repair methods without fully disassembling. If you have never done microelectronics, carefully read the section with warnings before you start work.
Should you disassemble the Mi Band 3 yourself? There's no clear answer: on the one hand, official repairs cost more than a new bracelet, on the other hand, careless actions can permanently put the device out of order, and we will help you assess your chances of success.
What you will need: tools and materials
To disassemble Xiaomi Mi Band 3 does not need professional soldering stations, but without specialized tools can not do.
- 🔧 Plastic mediators or blades (thickness 0.1-0.2 mm) - to separate the glued parts of the body!
- 🔥 Dryer or thermo-air station (with temperatures up to 80)°C) - for softening the glue. Even a household hair dryer is fine.
- 🧲 Magnetic screwdriver. T3 or T4 — for spinning four screws under the lid.
- 📦 Tweezers with curved ends - for careful extraction of plumes and small details.
- 🧴 Isopropyl alcohol (90%+) — Cleaning contacts and removing glue residues.
- 🔋 New battery or display (if you plan to replace) – original parts look for articles MDY-08-ER (battery or Mi Band 3 LCD (display).
- 📏 Plastic card or bank card as an alternative to a mediator for first attempts at opening.
Important: Don't use knives, scissors or other sharp objects, they will damage the body and plumes. If you don't have a thermophen, you can try to warm the bracelet in warm water (not higher than 50 ° C), but this is risky for electronics.
Preparation for disassembly: steps before opening the body
Before starting disassembly, follow these mandatory steps:
1. Completely discharge the bracelet (before switching off) - this will reduce the risk of short circuit.
2. Remove the strap and clean the body of the dirt with alcohol.
3. Prepare the workplace: a flat surface, good lighting, antistatic mat (if any).
4. Take a picture of the bracelet from all sides - this will help with the assembly.
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Pay special attention to protecting the display. If you disassemble the bracelet because of a cracked screen, tape it before heating, this will prevent fragments from entering the housing. If the purpose of disassembly is to replace the battery, check its voltage with a multimeter (must be 3.7-4.2V). If the voltage is below 3.0V, the battery could swell - in this case, disassembly is dangerous!
⚠️ Warning: If the bracelet has been in water or has been in contact with moisture, do not heat it with a hairdryer! Evaporation of the liquid inside the case can damage the board. In this case, leave the device in rice or silica gel for 24 hours before disassembling.
It is also worth considering that after disassembly, the Mi Band 3 will lose its factory sealability (IP68 protection class).If you plan to continue using the bracelet in water, additional silicone adhesive sealing (for example, LOCTITE 595) will be required.
Step-by-step: how to disassemble Xiaomi Mi Band 3
Now, to the most critical stage, follow the instructions strictly by step.
Step 1: Removing the back cover
1. Place the bracelet with the display down on a soft surface (for example, a napkin).
2. Heat the back cover with a hair dryer for 1-2 minutes, holding it at a distance of 5-7 cm.
3. Insert a plastic mediator into the gap between the lid and the housing (start at the button side). Carefully guide the mediator around the perimeter, gradually lifting the lid.
If the lid doesn't respond, heat it for another 30 seconds. Don't use excessive force, because there are fragile latches inside!
Step 2: Unscrewing screws and retrieving boards
1. Under the lid, you'll see 4 screws (usually under a T3 or T4 cross screwdriver) unscrew them and fold them into a separate container.
2. Carefully tuck the board with tweezers. It is attached to double-sided tape - do not pull sharply so as not to tear off the contacts.
3. Disconnect the display plume (it is fixed by a small connector) To do this, pull the black latch up, and then pull out the plume.
Photo of the display plume connector
Step 3: Replace the battery or display
For battery replacement:
- Solder off the old battery from the board (if there is no soldering experience, use a thermo-air station with a temperature of 250 ° C).
- Salt a new battery, observing polarity (+ and - marked on the board).
Check the voltage with the multimeter before assembly.
To replace the display:
Remove the old display by smacking it on the side (it is attached to double-sided tape).
- Install a new display, making sure that the plume is not twisted.
- Lock the plume in the connector by pressing the latch before clicking.
⚠️ Warning: If the bracelet does not turn on after the battery is replaced, check the charge circuit on the board. Often contact areas are broken off when the solder is not neat, in which case you will need to restore the tracks with conductive varnish (for example, Contac Cafe).
Step 4: Build the bracelet
1. Set the fee in place and secure it with double-sided tape.
2. Connect the display plume and lock the latch.
3. Twirl the screws (do not pull!).
4. glue the back cover to a new double-sided scotch (e.g. 3M 9448A) or sealant.
After assembly, check all the functions: touch screen, vibration, charging. If something doesn't work, unpack the bracelet again and check the connections.
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The most common build error is forgetting to lock the display plume with a latch, and without that, the screen won't respond to touch, although the image can be displayed.
Typical Problems and How to Avoid Them
Even with a careful disassembly, you can face unexpected problems, and here are the most common ones and ways to prevent them:
| Problem. | Reason. | Decision |
|---|---|---|
| The bracelet is not turned on after assembly. | No battery contact or damaged board | Check battery soldering, multimeter power chain |
| The screen doesn't respond to touch. | The display plume is not fixed or damaged | Take the bracelet apart, check the plume connector. |
| Vibration's not working. | Motor contact severed or plume damaged | Call the vibration chain, solder the contacts. |
| Bracelet not charging | Charging contacts or controller are damaged | Clean the contacts with alcohol, check the charging circuit |
| Artifacts appeared on the screen | The plume or display matrix is damaged | Replace the plume or display |
If after disassembly the bracelet stopped synchronizing with the smartphone, reset it to factory settings through the Mi Fit application. To do this, go to the Device Profile → Settings → Reset.
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If you happen to close contacts when soldering your battery, don't panic. Turn off the power, let the board cool for 10 minutes, and then check the fuse (a small black chip next to the battery), which often burns up to protect the board, which can be replaced with a similar one from the donor board.
Alternatives to Disassembly: When No Repair Is Needed
The Mi Band 3 is not always justified, and in some cases, the problem can be solved without opening the body.
- 🔋 Battery discharges fast → Try calibrating the battery: fully discharge the bracelet, then charge to 100% without interruption. Repeat 2-3 times.
- 📵 Not synchronized with your smartphone → Remove the bracelet from the Mi Fit app, restart the phone and add the device again.
- 💧 Water got in. → Place the bracelet in rice or silica gel for 24 to 48 hours!
- 🔄 Screen getting stuck or sensor bugging → Reset the bracelet to factory settings through Settings → Resetting in annex.
If the bracelet doesn't turn on after falling, try a hard reset: plug it into charging and hold the button for 10-15 seconds, sometimes helping with the firmware freeze.
Should you repair the Mi Band 3 or should you buy a new one? If the bracelet has served more than 2-3 years, and the repair requires replacing several components (for example, the board and the display), it is more cost-effective to purchase the Mi Band 6 or Mi Band 7. The price of a new device is often comparable to the cost of spare parts and risks.
Where to buy spare parts and how much it costs
Original parts for Xiaomi Mi Band 3 are hard to find, but there are proven alternatives:
- 🛒 Battery - the original article MDY-08-ER, 110 mAh capacity Cost: 300-500 ₽. Analogues: AK-383038 (chinese).
- 📺 Sensor display – the original module will cost 800-1200 ₽. Cheap analogues (from 500) ₽) They often have poor sensitivity.
- 🔧 Back cover with button - sold complete with screws, price 200-400 ₽.
- 🔌 Trains and connectors – rarely sold separately, usually come complete with a display.
Where to buy:
- AliExpress is cheap, but it's a long wait (2-4 weeks) and look for sellers with a rating above 98%.
- Yandex Market / OZON is fast delivery, but prices are higher by 20-30%.
- Local service centers – sometimes sell used parts from donor devices.
- Groups in VK/Telegram – for example, “Repair Xiaomi” or “Spare parts for gadgets”.
⚠️ Warning: When buying a battery, check its capacity with a tester! Unscrupulous sellers often indicate overestimated parameters. The original Mi Band 3 battery should show 105-115 mAh.