Modern smartphone users often face a situation where the power adapter stops performing its functions or works unstable. Xiaomi Redmi power units, despite their high reliability, can fail due to voltage surges, mechanical damage or natural wear of components. Disassembly of the device allows you to diagnose the problem, replace a fuse or restore a broken wire, which is much cheaper than buying a new original accessory.
Before you start dismantling, it’s important to understand that opening the charger case gives you no warranty and requires strict precautions. Inside are elements that can retain residual charge even after disconnecting from the network, so rushing is not allowed. In this article, we will take a detailed look at the process of opening popular Xiaomi power supply models, including those that have a monolithic case sealed around the perimeter.
To do this successfully, you'll need not only a desire to save money, but also a minimal set of tools, and a basic understanding of how electronics work. We'll look at the typical malfunctions that Redmi smartphone owners face, and provide a step-by-step algorithm for action. If you're willing to take the risk and try to reanimate the device, follow each step of the instruction carefully.
Tools and workplace preparation required
High-quality disassembly of electronics is impossible without the appropriate tools that will ensure the accuracy and safety of the process. To open Xiaomi power supplies, you will need a thin flat blade that can be part of a special repair kit or made from an unnecessary plastic card. Metal items such as a knife or screwdriver should be used with extreme caution so as not to damage the internal boards and not cause a short circuit.
In addition to cutting tools, be sure to prepare a soldering iron with a thin sting, solder and flux, as in most cases, repair is not complete without soldering contacts or replacing capacitors. You will also need a multimeter to check the integrity of the chains and the presence of voltage at the output, which will accurately determine the faulty node. Don't forget about the magnifying glass, as the elements inside the power supply are very dense.
☑️ Preparation for repairs
The workplace should be well lit and protected from moisture, as the electronics do not tolerate dampness. It is recommended to use an antistatic mat or at least a dry clean surface to prevent accidental damage to the chips by static electricity. Before starting work, make sure that the power supply is completely disconnected from the network and not connected to it for several hours.
⚠️ Note: It is strictly forbidden to open the power supply if it has just been disconnected from the power grid, since the capacitors inside can keep a high charge.
Design and features of Xiaomi power supplies
Xiaomi Redmi’s power supplies, especially Quick Charge and Power Delivery, have complex internal architectures, often made of durable plastic and lacking visible screws or latches, giving the illusion of a solid design. Inside, there’s a pulse converter that converts the alternating voltage of the grid into the constant low voltage needed to charge the smartphone’s battery.
The main components of the board are the transformer, rectifying diodes, charge controller and filter capacitors. In models with support for Fast Charge, there is an additional chip responsible for coordinating charging protocols between the adapter and the device, which is the chip that often fails when using poor-quality cables or voltage surges in the network.
Why are Xiaomi blocks so strong?
There are two main types of body design: screws and adhesive/ultrasonic. The former are less common and mostly in older or specific models, whereas modern Redmi adapters almost always have a sealed case. Understanding the type of design will help you choose the right opening strategy and avoid breaking plastic walls.
| Type of body | Autopsy method | Difficulty | Risk of damage |
|---|---|---|---|
| Screw. | Spinning screws | Low. | Minimum |
| glue | Blade heating and opening | Medium | Medium. |
| Ultrasonic. | Sliced or compressed | Tall. | High-pitched |
| monolithic | Destruction of the hull | Extremely extreme. | critical |
The process of opening the case without visible screws
The most common case is when you pick up a Xiaomi power supply and you don't find a single screw. The seam between the two halves of the case is almost invisible, and the assembly itself is very tight. First, look carefully at the perimeter of the device in bright light to find microscopic gaps or places where the plastic is less thick.
Take a thin flat blade or a special tool to open it, and gently insert it into the seam between the halves of the body. Move the blade along the perimeter, trying to layer the glue or break the ultrasonic welding. Don't put too much effort into one point, you'd better walk around a few times, gradually going inwards.
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To facilitate the opening process, you can slightly warm the body seam with a hair dryer for 1-2 minutes. The plastic will become softer, and the glue will lose its properties, which will allow you to separate the halves with less effort.
In some cases, especially with high-power models, the body can be so strong that you can't do without damaging the outer shell. If the blade doesn't help, you can use a thin sheet of metal hacksaw to make a neat incision at the seam, but act extremely carefully so that you don't hit the insides. Once the body is opened, you will see a board attached inside, often on additional latches.
⚠️ Note: When using force to open the case, there is a high risk of crushing the internal components or damaging the insulation of the wires leading to the plug.
Diagnostics and troubleshooting
Once the board is successfully removed from the case, you need to do a visual inspection of the components, look for signs of burns, blackening, capacitor bloating or detached contacts, and often the cause of failure is a fuse that is burned at the AC input, or a swelled capacitor at the output.
Use a multimeter in vertebrae mode to check the integrity of the circuits. Start by checking the input circuit: make sure that the current reaches the transformer. If the fuse is intact but there is no voltage, the problem may be in the diode bridge or primary winding of the transformer. To check the output parameters, you can gently apply the voltage (safety!) and measure the output with a voltmeter.
A typical problem for Xiaomi charging is to separate the wire from the board at the soldering site. Visually, this may not be noticeable, but as the cable moves, the contact may disappear. Carefully examine the place of entry of the cable into the case and the point of its soldering to the board. Also, resistive dividers responsible for determining the type of device connected often fail.
If you don't see any visual defects, you should look at the charge controller, which is the chip that controls the current flow, and it's hard to diagnose a malfunction without an oscilloscope, but if all the other elements are intact and no charging, there's a high probability of a problem with the control chip.
Replacement of components and assembly of the device
If you find a faulty element, such as a capacitor or fuse, you need to replace it. Use a soldering iron at about 300-350 degrees Celsius. Carefully solder the old component, clean the solder holes and install a new element with similar characteristics. It is important to observe polarity when soldering capacitors and diodes.
If the problem was a torn wire, clean the ends of the veins, smear them and securely solder to the contact areas on the board. Make sure that the soldering is of high quality and does not short circuit with neighboring elements. After repair, assemble the body in reverse order, fastening the halves with glue or tape if the factory latches were damaged.
Before final assembly and closure of the housing, test the power supply, connect the power supply to the mains and measure the output voltage with a multimeter, it must meet the declared characteristics (for example, 5B, 9B or 12V depending on the mode). If all parameters are normal, you can fix the board inside the housing.
⚠️ Warning: Never leave a repaired power supply turned on unattended during the first hours of operation to ensure there is no overheating or burning smell.
Typical repair errors and safety measures
One of the most common mistakes is to neglect safety when working with the mains voltage. Even after disconnecting from the outlet, the capacitors in the 220V circuit can retain a deadly charge. Before touching any elements of the board, you need to discharge the high-voltage capacitor by closing its contacts with a dielectric or through a resistor.
Another common mistake is to use components with inadequate performance, and replacing the capacitor with a lower voltage or other capacity can cause the device to break down or even explode again, and always pick up parts with voltage margins and identical in capacity and type.
Also, don't ignore the quality of the soldering. Bad contact can cause sparkling and heating, which will lead to melting of the case and fire. If you're not sure about your soldering skills, you'd better trust the repair to the professionals or replace the whole device. Repair of pulsed power supplies requires certain knowledge and skills.
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High-quality soldering and use of original or high-quality analogues of components is the key to safe and long-term operation of the repaired power supply unit.
When repairs don’t make sense
Despite the desire to reanimate the device, there are situations when repairing it is not economically or technically feasible.If the transformer or main controller is burned, the cost of replacing these components with work can exceed the price of a new adapter.
If the housing of the power supply is severely deformed, melted or has cracks that violate its integrity, the operation of such a device is dangerous, the plastic could lose its dielectric properties, and the use of such an adapter threatens to shock, in such cases it is wiser to purchase a new certified power supply.
It is also worth refusing to repair if you do not have the necessary tools and experience. Trying to fix a complex electronic device on your knee can lead to disastrous consequences, including damage to the smartphone itself that you plan to charge.