Xiaomiβs power units are known for their compactness, efficiency and reliability, but even they are not immune to breakdowns. Burnt capacitors, damaged connectors or the consequences of power surges may all require opening the case for diagnosis or repair. However, disassembling the power supply (especially pulsed) carries risks from loss of warranty to electric shock or short circuit.
In this article, you will find a step-by-step guide with photos of key stages, a list of necessary tools and unique tips for working with different Xiaomi models (including Mi Charge Turbo, Redmi Note and others), we will also analyze which parts often fail, how to check them with a multimeter and when it is best to consult a specialist.
β οΈ Warning: Disassembly of the power supply is associated with high voltage (up to 220V). Even after disconnection from the network, the capacitors can retain a charge that can cause serious damage to health. If you do not have experience with electronics, take the device to the service center.
What power supplies Xiaomi can disassemble on their own?
Not all Xiaomi power supplies are equally easy to disassemble, and here are key criteria to help determine whether to get to work:
πΉ Type of body:
- π§ Glued halves (for example, Mi) 18W or Redmi 20W) β require careful separation with a knife or mediator, and the risk of damage to the body is high.
- π© Screw connections (found in powerful models from 33W, For example, Mi Charge Turbo 30W/65W) β are easier to understand, but screws can be under a non-standard screwdriver.
- π² Compounded (cheap non-original blocks or old models) β disassembly is almost impossible without destruction.
πΉ Power and purpose:
- π± Charging for smartphones (5Wβ33W) β They are usually repairable, but require jewelry precision.
- π» Laptop blocks (65Wβ100W, Xiaomi Mi Notebook Air β more difficult to disassemble, often have additional protection from opening.
- π Universal adapters (for example, Xiaomi Multi-Port) β can contain several boards, which complicates the diagnosis.
πΉ Warranty status: If the power supply is warranty, opening the case automatically cancels it. Check the date of purchase in the check or the Mi Home app - it may be easier to exchange the device under warranty.
Tools and materials: what you need for disassembly
Prepare everything you need before you start, and even one tool can damage the body or internal components.
| Tool/material | Appointment | Where to buy |
|---|---|---|
| Plastic mediator or guitar mediator | Disconnection of the glued halves of the shell without scratches | Musical Products Stores, AliExpress |
| Set of screwdrivers (cross, flat, Torx) T5βT10) | The screws in the power supply often have non-standard slits. | Any tool store (e.g. iFixit) |
| Multimeter (with mode of checking diodes and capacitors) | Diagnostics of faulty elements after disassembly | Ozone, Citilink, Beru.ru |
| Stolen iron (power 30β40W) + solder + flux | Replacement of burnt resistors, capacitors or connectors | Radio markets, AliExpress |
| Strain or shrink tube | Isolation of bare contacts after repair | Any hardware store |
β οΈ Note: If you plan to solder, use lead-free solder - it is less toxic when heated. Also be sure to work in a well-ventilated room: when some elements (for example, capacitors) overheat, harmful fumes are released.
π‘ Tip: Before disassembling, take a photo of the power supply from all sides, which will help to properly assemble the body back, especially if there are guides or locks inside.
Step-by-step: how to disassemble the power supply Xiaomi
Consider the universal algorithm on the example of the popular model Xiaomi Mi 20W Fast Charge (MDY-11-EP). For other power supplies, the steps may differ slightly.
π§ Step 1: Disconnection and discharge of capacitors
- β‘ Disconnect the power supply from the socket and device.
- π Wait at least 10-15 minutes β this is enough time to discharge high-voltage capacitors.
- π To accelerate discharge, the unit can be connected to the incandescent light bulb (40β60W) 1-2 seconds.
π§ Step 2. Separation of the hull
- π Check the case for screws. 20W They are hidden under a sticker with characteristics (carefully slap it with a knife).
- π© Unscrew the screws with a Torx screwdriver T5 (in some models β T6 cross-bow).
- π‘οΈ If the body is glued, insert the mediator into the seam and guide it gently around the perimeter, splitting the glue. Don't put too much effort into it, the plastic can crack!
βοΈ Checking before disassembly
π§ Step 3: Extracting the fee
- 𧲠When you take the top cover off, you'll see a board attached to the bottom half of the body.
- π Notice the power connector (where the cable is inserted) -- it can be soldered to the board. Don't pull the wires!
- πΈ Take a picture of all the elements before touching the board.
π§ Step 4: Diagnostics of malfunctions
Now that the fee is in front of you, check it for visible damage:
- π₯ Blackened or bloated capacitors - a sign of overheating.
- π Cracks on the tracks or detached contacts.
- π₯ Burnt resistors (usually blacken or crack).
- π oxidized or burnt connectors (especially USB-port).
Critical information: Xiaomi power supplies often use a chip controller SC8903 (If it is overheated or has burn marks, repairs may not be cost-effective, the cost of replacing exceeds the price of the new unit.
Typical malfunctions of Xiaomi power supplies and their elimination
Most of Xiaomiβs power supply breakdowns are caused by overloads, power surges, or mechanical damage, and here are the most common problems and ways to solve them:
π 1. The block does not show signs of life (the indicator does not burn, does not warm up)
- π Check the fuse (usually located near the 220V entrance). If it burns out, replace it with a similar one at face value.
- π Examine the network filter (waristor, throttle) - with a voltage surge, it could fail.
- π Call the primary circuit (from fork to transformer) with a multimeter, and the break indicates damage to the track or element.
π₯ 2.The unit warms but does not charge the device
- π Check the output voltage with a multimeter. If it is lower than the nominal voltage (for example, 4.5V instead of 5V), the problem is in the stabilizer or transformer.
- π Look at this. USB-connector - often oxidized contacts +5V and GND.
- π Try connecting another device - if the problem persists, the power supply is to blame.
β‘ 3.The block sparks or smokes when connected
- β Shut off the grid immediately! This is a sign of a short circuit.
- π Look for broken elements on the board β usually capacitors or diode bridges.
- π§ If there is no visible damage, the problem may be in the transformer - its replacement will cost more than a new unit.
β οΈ Note: If the power supply Xiaomi began to emit a high-frequency squeak when working, this is a sign of a malfunction of the pulse transformer or key transistor. Self-repair in this case is extremely risky - it is better to buy a new unit.
How to check the capacitors with a multimeter?
Assembly of the power supply after repair: key points
Once the fault has been fixed, the power supply must be properly assembled to avoid short circuits or repeated breakdowns.
π§ 1.Pre-assembly check
- π Check the fee again for forgotten screwdrivers or solder debris.
- π Call the multimeter of the input and output chain for no short circuit.
- πΈ Check the photos taken before the demolition.
π§ Insulation and fixation of elements
- π₯ If you replaced the elements, isolate their legs with a shrink tube or tape.
- π© Twisting screws tightly but without bigotry - tug-of-tat can damage the fee.
- π² If the body is glued, use double-sided tape or glue. B-7000 half-fix.
π§ 3. Test inclusion
- β‘ Connect the block to the network through a network filter (in case of short circuit).
- π Check the output voltage with a multimeter before connecting the device.
- π± If everything is in order, connect your smartphone or laptop and observe the behavior of the unit (no heat, sparks or extraneous sounds should be observed).
β οΈ Warning: If the power supply starts to buzz or vibrate after assembly, this is a sign of poor fixation of the transformer or throttle. Disassemble the unit and fix the elements more reliably - vibration can lead to a break in the tracks.
π‘
After repair, sign the power supply with a marker (for example, "repaired 05.2026"), which will help to track if the problem recurs and warn other users.
When repairs are inappropriate: signs of hopeless breakdowns
Not all Xiaomi power supply malfunctions are repairable at home, and here are some cases where itβs easier and safer to buy a new power unit:
π« 1. Impulsive transformer damaged.
It's the heart of the power supply, and replacing it requires precise measurements (transformation rate, power) and special rewinding equipment, and the cost of a new transformer often exceeds the price of the entire unit.
π« 2.The controller's chip burned.
Xiaomi blocks use specialized chips (for example, the chips are used in the units, SC8903, BP2832A). Their replacement requires a soldering station with precise temperature control and experience with the use of the air. SMD-component.
π« 3.The body has melted or deformed
If the plastic melts because of overheating, it's almost impossible to find a new case, and even if the board is working, it's dangerous to put the block into a damaged case, because it can't withstand the load.
π« 4.Repeated failed repair attempts
If the block has been disassembled several times and the problem is not fixed, further experiments may lead to fire or electric shock, in which case it is better to take the unit for disposal and buy a new one.
π‘ Tip: Before buying a new power supply, check it for compatibility with your device. for example, Xiaomi Mi 11 supports Quick Charge 4+, But for full charging speed, you need a unit with a power of at least 33W.
Safety when working with power supplies: what you need to know
Working with pulsed power supplies involves risks that are often underestimated, and here are key safety rules to help avoid injuries:
β‘ Discharge of high-voltage capacitors
Even after disconnection, the capacitors in the primary circuit (220V) can hold a charge for up to several days to discharge them safely:
- π Use a resistor with a nominal value of 10-20 kΞ©, connecting it to the terminals of the capacitor for 5-10 seconds.
- π§ Never close the contacts with a screwdriver or tweezers - this will lead to sparkling and damage to the elements.
π₯ 2. Protection against static electricity
Many of the items on the board (especially MOSFET-Transistors and chips are sensitive to statics, so they don't get damaged:
- π Wear an antistatic bracelet or periodically touch a grounded object (such as a heating battery).
- 𧡠Do not work on carpet or in wool clothing.
π¨ 3. soldering and ventilation
Salting works emit harmful fumes (from flux, solder, plastic) to avoid poisoning:
- πͺ Work near an open window or use an hood.
- π· Wear a respirator or medical mask.
- π₯ Do not overheat the board - the soldering iron temperature should not exceed 350Β°C.
β οΈ Warning: If you smell burning or see smoke on the first switch on after repair, immediately disconnect the unit from the network and disassemble it for inspection.
π‘
Even if the power supply is working after repair, do not leave it unattended during the first hours of operation.