Replacement of the lock button on Xiaomi: from disassembly to soldering

The lock button on Xiaomi smartphones is one of the most vulnerable elements: it fails due to moisture, mechanical damage or trivial wear after thousands of presses. If your Redmi Note 10, POCO X3 or Mi 11 stopped responding to short/long press, turns on only from charging or does not lock the screen at all, the problem is the button. In 80% of cases, it can be replaced by yourself, saving on the service center.

In this article, a step-by-step photo guide on how to disassemble a phone, remove an old button, solder a new one (or replace a flexible plume entirely) and assemble a device without consequences. We will look at three repair methods: from simple module replacement to soldering a micro-switch on the board, and learn how to check the performance of the button before disassembly and where to buy quality parts for Xiaomi without the risk of running into a fake.

Signs of failure of the lock button

Before you disassemble the phone, make sure that the problem is in the mechanical part.

• 🔘 The button does not lock the short press (does not block/unlock the screen), but it works on the long one (turn off/reboot).
• 💦 The phone is only turned on when connected to a charger or through ADB (sign).
• 🔊 The button "fails" or emits a creak / crunch when pressed (mechanical wear and tear).
• 🌡️ The device spontaneously restarts or turns off (may indicate a closure of contacts).
• 🔋 After falling or getting moisture, the button stopped working completely.

If you see any of these signs, you probably need to replace them, but you can rule out software failures: try resetting to factory settings (Settings → About Phone → Reset) or scrolling through the Fastboot. If the problem persists, start repairing.

⚠️ Note: On Xiaomi models with an ultrasonic fingerprint scanner in the button (e.g. Mi). 10T, Redmi K40) Replacement requires additional calibration of the sensor after installing a new part!

Replacement tools and parts

For repairs you will need:

Important: When buying a plume, check the exact phone model and board revision (for example, the Redmi Note 9 Pro has 3 versions of the plume!). An incompatible part may not become a connector or not work after installation.

Disassembly of the phone: step-by-step instructions

The disassembly algorithm is the same for most Xiaomi models (with the exception of flagships with adhesive display, for example, the Mi 11 Ultra).

1. Turn off the phone and remove it. SIM-scatter-card.
2. Heat the back cover with a hair dryer (temperature 60-70 ° C) around the perimeter for 2-3 minutes - this will soften the glue.
3. Put a plastic lid on the lid, starting at the corners. NFC-antennae (e.g, POCO X3 NFC) Be careful, the antenna is glued to the cover!
4. Unscrew the screws with a cross screwdriver (usually 6-8 pieces). screws of different lengths - remember the location of each!
5. Disconnect the battery plume (use a plastic blade to avoid damaging the contacts).
6. Remove the metal plate covering the motherboard and access the power button.

At this point, you’ll see a flexible plume with a button (usually screwed to the board with 1-2 screws) if the button is soldered into the board (like on the Mi 9 or Mi 10), soldering will be required.

Is the phone off?|Whether extracted SIM-memory-card?|Whether the tools (scapula, screwdriver, hair dryer) are ready)?|Is the location of the screws photographed?|Is the battery off?-->

Methods of replacing the lock button

Depending on the design of the phone, choose one of the ways:

1. Replacement of the flexible plume (the simplest method)

Suitable for 90% of Xiaomi models, where the power button is part of a separate module.

1. Unscrew the screws that lock the button plume.
2. Carefully slap the plume connector on the motherboard (use a plastic shoulder blade!).
3. Set the new plume in reverse order. Make sure the contacts match!
4. Lock the plume screws and check the operability of the button before assembly (connect the battery).

Replacement of the micro-switch (soldering)

If the button is soldered into the board (for example, on the Mi 8 or Mi Mix 2S), you will need to:

1. Remove the old switch by heating the contacts with a soldering iron on both sides (temperature 300-350 ° C).
2. Clean the sites from the residues of solder flux and overflow.
3. Install a new micro-switch (buy with stock - they are fragile!).
4. Seal the contacts, avoiding overheating the board (maximum 5 seconds for each contact).

3. Replacement of the entire button board (for models with side sensors)

On some devices (e.g. Redmi) K50 Gaming, the power button is integrated into a common circuit board with a volume control, and in this case, you have to replace the entire module, and the cost of this part is from 1,500. ₽.

⚠️ Note: Do not use acid-based active flux (e.g. LTI) when soldering-120) — It's corroding the board tracks. Only neutral fluxes like this. RMA-223 Kester 2331!

Phone assembly and check

After changing the button, assemble the phone in reverse order, following these rules:

• 🔧 Tighten the screws cross-cross to avoid skewing the fee.
• 🧲 Before installing the back cover, check the operation of all buttons (volume, power) and sensors.
• 🔋 Connect the battery last - this will eliminate short circuit during assembly.
• 📱 If the screen does not turn on after assembly, check the connection of the display plume and battery.

After the phone is turned on:

1. Check the reaction to the short/long press of the power button.
2. Make sure that the fingerprint scanner (if any) is working properly.
3. Run the sensor test through the engineering menu (#4636###).

💡

If the phone doesn't turn on after assembly, but vibrates when charging, check the contacts of the battery plume. Often they leave when the lid is not installed neatly.

Where to buy quality parts for Xiaomi

Avoid cheap parts with AliExpress without reviews - they often break down after 1-2 months.

• 🛒 Official partners Xiaomi: Mi Store, Xiaomi Shop (parts for flagships).
• 🔧 Specialized stores: Fixez, Repair-Universe, iFixit (6-month warranty).
• 📦 AliExpress (verified sellers only): Xiaomi Original Parts Store (rating 99.1%) Digi-Flash Official Store (specializing in plumes) HWS Mobile Parts (there are video reviews of spare parts)

Tip: When buying a power button plume, look for the phrases "100% tested", "OEM quality" or "original flex cable" in the description. Avoid spare parts marked "compatible" - these are low-quality Chinese copies.

Frequent Mistakes and How to Avoid Them

Even experienced craftsmen make mistakes when replacing the lock button.-5 Failures and How to Prevent Them:

💡

If you change the button, but the phone spontaneously reboots, the problem is that the plume is in poor contact with the board. Take the device apart and check for the fix.

FAQ: Answers to Frequent Questions