Modern power adapters Xiaomi is famous for their reliability and high density layout, but even high-quality electronics are subject to wear. Often users are faced with a situation where the original charger stops signaling, makes extraneous sounds or simply does not turn on.
Disassembly of the power supply is a process that requires not only tools, but also strict safety, because there are elements inside that retain residual charge. Incorrect actions can lead to short circuit or injury, so the procedure should be approached with the utmost responsibility and care. In this article, we will discuss in detail the algorithm of actions that will allow you to open the case without damage and conduct an initial diagnosis.
Before you start physically affecting the device, you need to make sure that the problem lies in the adapter, and not in the damaged cable or smartphone connector. If you have determined that the malfunction is localized in the unit, then the next steps will help you restore it to work or safely dispose of it.
Workplace preparation and necessary tools
The quality of any electronics repair begins with the proper organization of the workspace. You need a table with good lighting to distinguish the small components on the board without losing cogs or latches. The main tool for opening the case will be a thin plastic card or a special mediator, since metal objects can damage the plastic or close contacts.
To work with the internal elements, you will need a set of precision screwdrivers, usually cross sized PH00 or PH000, and you will also need tweezers with curved ends for easy extraction of small parts and a multimeter for subsequent inspection of the power chains.
- 🔧 A set of screwdrivers with magnetic tips for working with micro-screws.
- 📱 Plastic blade or mediator for opening the body without scratches.
- 🔍 Loop or magnifying glass for inspection of small board elements.
- ⚡ Multimeter to check circuit integrity and voltage.
⚠️ Before starting any work, be sure to disconnect the adapter from the electrical network and wait for a minimum. 5-10 This is necessary to discharge high-voltage capacitors, which can retain a dangerous charge.
Make sure that the room is free of drafts that can carry light parts, and the table surface is clean and dry.Using an antistatic mat or bracelet will be an added benefit to protect sensitive electronics from static discharge, although in the high-voltage part of the power supply, this is less critical than in smartphones.
Design analysis and search for hidden screws
Xiaomi engineers often use a monolithic body design, where visible screws are completely absent.This is done to improve ergonomics and dust protection, but significantly complicates access inside. USB-plug-pin.
Often, under a decorative sticker with technical information, fasteners are hidden. Carefully heat the sticker with a hair dryer or simply gently tuck the edge of it to check if there are screws underneath. In some models, the fasteners hide under rubber legs or in indentations that are difficult to see without good lighting.
If no external screws are found, then the body is assembled on plastic latches, in which case you need to find a thin seam between the two halves of the body, usually passing along the perimeter of the device and can be barely noticeable, and using a magnifier at this stage will help determine the exact place where the halves dock.
| Type of attachment | Location. | Tool. | Risk of damage |
|---|---|---|---|
| Screws under the sticker | Central part | Thin screwdriver | Low. |
| Plastic latches | Perimeter. | Plastic card | Medium. |
| Ultrasonic welding | Seam in a circle | Thin blade | High-pitched |
| Hidden screws. | Under the rubber legs | Tweezers + screwdriver | Low. |
Understanding the type of assembly allows you to choose the right opening strategy, so if you make the mistake of breaking the weld where there are screws, you can permanently damage the case, so a thorough visual inspection is critical.
The process of opening the body without damage
To separate the halves of the case connected by the latches, you need to insert a plastic card or mediator into the seam. Move along the perimeter, carefully pressing and making reciprocal movements. Don't try to open the block from one edge, this will break the plastic tongues.
Move gradually, snapping the locks in a circle. You will hear the characteristic clicks when the latches are released. If the body resists, do not use excessive force - better check again if you missed a hidden screw or adhesive connection.
☑️ Pre-mortem checks
In cases where the halves are glued or soldered by ultrasound, it may be necessary to carefully cut the seam with a thin scalpel or blade, and do this very slowly, trying not to damage the internal components that may be close to the walls of the case.
⚠️ Attention: When you cut the seam or press hard, you risk damaging the inner board or tearing off the wires going to the LED light.
Once all the latches are snapped, don't pull the halves sharply to the sides. Inside, there may be a wire connecting the button or an indicator to the main board. First, inspect the insides and, if necessary, disconnect the connectors with tweezers.
Diagnosis of internal components and schemes
Once you successfully remove the board from the case, you'll see a complex electronic circuit, and the main components that most often fail are the input and output capacitors, and the fuse, and the bloating of the capacitors is visible to the naked eye, and the top of the capacitors becomes convex.
Use a multimeter in vertebrae mode to check the integrity of the fuse. If it burns out, this often indicates a more serious problem inside the circuit, such as a breakdown of the transistors or diode bridge, in which case a simple change of the fuse can lead to a reburnout or short circuit.
- 🔋 Capacitors: Check for swelling and leakage of the electrolyte.
- 🛡️ Safety: Must show zero ohms, otherwise it's burned out.
- 🔌 USB-connector: check the reliability of soldering contacts on the board.
Pay special attention to the location of the network cable and USB-Because of the constant mechanical load on the cable, these places often crack, which leads to the loss of contact.
What to do if the condenser is blown?
If no visual defects are found, a more in-depth diagnosis using an oscilloscope or checking each element of the circuit separately will be required, but for most users, it is enough to replace clearly damaged parts or restore contact with soldering.
Replacement of elements and re-establishment of contacts
To replace the burnt elements, you'll need a soldering iron with a thin sting, solder and possibly a flux. It's important to keep the temperature in order not to overheat the board and peel the tracks. When you solder the capacitors, try not to put excessive effort on their body.
If the problem was a passing contact USB-So, if you plug in, you warm up the soldering area carefully, and you add some fresh solder, it will strengthen the connection, and it will restore the transmission of current to the cable, and make sure that the solder does not create a jump between the adjacent contacts.
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Use solder paste instead of the usual solder to work with small ones SMD-components – this will greatly simplify the process and improve the quality of the connection.
When installing new components, strictly observe polarity, especially for capacitors and diodes. Incorrect polarity will cause the new part to instantly fail and possible damage to the entire board when first turned on.
⚠️ Warning: Never use a refurbished power supply without first checking. An error in assembly or soldering can cause a high voltage to be applied to the smartphone, which will disable it.
After the soldering works, be sure to clean the board of flux residues with alcohol or a special cleaner. Residues of chemistry can cause corrosion or leakage over time.
Device assembly and final testing
Before the final assembly of the case, you need to conduct an initial test, connect the power supply to the network through a fuse or in a safe place, away from flammable objects. USB-port, it must conform to the declared characteristics (usually 5B, 9B or 12B depending on the mode of operation).
If the voltage is normal and there are no extraneous sounds, you can assemble the body, make sure that all the wires are laid correctly and not sandwiched between the halves of the body, which could cause them to damage or short circuit.
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The main criterion for successful repair is a stable output voltage without pulsations and the absence of heating of the body when working under load.
Close the halves of the case, snapping all the locks to the characteristic click. If screws were used, twist them without undue effort, so as not to tear the thread in the plastic. Stick the technical sticker in place if it is preserved.
The final step is to connect the smartphone to check the charging speed, if the device is charging correctly and not overheating, the repair can be considered successful, otherwise it is worth reconsidering the feasibility of further repair or replacement of the unit.