Xiaomi car chargers are popular for their compactness, power and reliability. However, even the best technology can fail: stop charging, warming or making extraneous sounds. In such cases, disassembling the device is the first step to diagnosis or repair. But how to properly open the case without damaging the internal components? This article will help you understand the nuances of the process, from tool preparation to analysis of typical malfunctions.
Many users are afraid to disassemble chargers for fear of electric shock or final breakdown. Indeed, working with electronics requires caution, but with simple rules, the risks are minimized. The main thing is to understand that Xiaomi car charges (for example, Mi Car Charger or Redmi Car Charger models) have a specific design different from household adapters. Their body is often glued or fixed with latches, and the internal circuit can include elements of protection against voltage drops.
Before starting a disassembly, it is worth assessing the feasibility of repairing. If the device is under warranty, it is better to contact the service center. If the warranty period has expired or the breakdown is obvious (for example, a melted case), self-disassembly can save time and money. In this article, we will look at step-by-step instructions, necessary tools, and also give tips for diagnosing malfunctions.
What tools will be needed to disassemble
Xiaomi doesn't need professional tools to cleanly disassemble car charging, but it doesn't need a minimum set.
- π§ Plastic blade or mediator - for disconnecting the glued parts of the body without scratches.
- π¨ Thin screwdriver (cross or flat) β Some models have screws under the lid.
- 𧲠Magnetic substrate or bowl β to avoid losing small parts (screws, springs).
- π Loop or magnifying glass - for inspection of chips and tracks on the board.
- πΈ Smartphone with camera β to photograph the disassembly process and the location of parts.
If you plan not only to disassemble, but also to repair the charging, additionally can be useful:
- π₯ A soldering iron with a thin sting (power 20-30 W) is for repairing contacts.
- π§ͺ Isopropyl alcohol - for cleaning board from oxidation.
- π Multimeter to check output voltage and circuit integrity.
Important: don't use metal tools to open the case unless you're sure they're accurate. One careless move can damage the PCB or USB- connector, making the device non-repairable. If you don't have a plastic blade at hand, you can use an old bank card -- it's flexible enough to scratch the plastic.
Preparation for disassembly: security measures
Electronics are always risky, so you need to be safe before you disassemble.
β οΈ Warning: Even disconnected charging can contain charge-storing capacitors. It is not recommended to touch the board with your bare hands β use dielectric gloves or hold on to insulated parts of the case.
- β‘ Turn off the charge from the lighter at least 10 minutes before disassembly - this will discharge the capacitors.
- π‘οΈ Check the body temperature. If the charge was warmed while running, let it cool down -- heating can warp the plastic when opened.
- π§Ό Work on a clean surface, and dust and debris can get inside the device and cause a short circuit.
- π΅ Disconnect your phone and other devices from charging β even if itβs faulty, an accidental circuit can damage the connected appliances.
If you notice traces of melting, blackening or the smell of burning on the case, it is better to disassemble in the open air or in a well-ventilated room. In some cases, overheating can lead to the release of toxic substances from plastic or solder.
You also need to pre-design a circuit or photos of your model's internal device. For example, the Mi Car Charger Pro and Redmi Car Charger chargers have different layouts of boards, and without visual guidance, you can accidentally damage important elements. If you're not sure about yourself, take photos of each stage of the disassembly, which will help you put the device back together properly.
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Before disassembling, check the multimeter charging in "spinning mode." If the USB output is no resistance or it is going to zero, the problem is most likely the short circuit of the board.
Step-by-step instructions: how to disassemble the body
Xiaomi car chargers typically have two types of case attachment: latch or glue. Consider both.
Option 1: Latch housing (most models)
- Take a plastic blade and gently insert it into the gap between the top and bottom of the body, starting at the corner where the first latch is usually located.
- Smoothly drive the blade along the seam, alternately snapping the locks. Don't put too much effort - if the body does not lend itself, there may be hidden screws.
- Once all the latches are open, remove the top cover. Be careful, wires or spring contacts may be glued inside.
Option 2: Glued body (rarely, but occurs)
If the body is glued, a more delicate approach will be required:
- Heat the body with a hair dryer (temperature not higher than 60 Β° C) for 1-2 minutes. This will soften the glue.
- Carefully slap the edge with a spatula and slowly separate the parts. If the glue is too strong, you can use a thread (for example, a dental one) pierced between the parts of the case.
- After disassembly, remove the glue residues with alcohol or acetone, but do not allow liquid to enter the board.
Inside the building you will see:
- π Printed circuit board with chips and capacitors.
- π USB- connector (or multiple if multiport charging).
- π Spring contacts for connecting to a lighter.
- π‘οΈ Protective elements (waristors, fuses).
βοΈ Checklist before disassembly
Internal design analysis: what can be repaired on your own
After opening the case, it's time to assess the condition of the internal components, and here are the most common malfunctions and ways to fix them:
| Malfunction | Reason. | Renovation method |
|---|---|---|
| Charging doesn't give voltage. | Chain break, fuse burnt out | Call the multimeter, replace the fuse |
| The device is warmed, but does not charge | Short circuit, faulty capacitor | Replace the bloated capacitors, check the diodes |
| Slow charging. | Oxidation of contacts, wear USB- connector | Clean contacts with alcohol, bend USB- legs |
| Extraneous noise (squeaking, crackling) | Failure of the throttle or transformer | Replacement of the element (requires soldering skills) |
Pay special attention to the fuse, which is the most vulnerable element in car charging. It is usually located USB- connector and looks like a small black or green cylinder with metal caps. If the fuse is burned (apparently blackened or broken), it can be replaced with a similar one with the same nominal value (usually 2A or 3A).
Also check the capacitors β if they swell or leak, they need to be replaced. This will require a soldering iron and new capacitors with identical parameters (capacity and voltage are indicated on the body). For example, Mi Car Charger Pro models often fail capacitors per 1000 ΞΌF Γ 6.3V.
β οΈ Warning: If the board shows traces of soot or melted tracks, self-repair can be dangerous. Such damage often indicates serious problems with the power chain, and further operation of the charge can lead to fire.
How to check the diode bridge multimeter?
Common Mistakes in Disassembly and How to Avoid Them
Even experienced craftsmen sometimes make mistakes that lead to the final breakdown of the device, and here are the most common ones:
- π¨ Using metal tools to open the case, which causes scratches, circuits and damage to the printing tracks.
- π₯ Overheating of the board with a soldering iron. Excessive temperatures can detach tracks or damage the chips.
- π§ Liquids are put on a board when cleaning, and even isopropyl alcohol in large quantities can cause corrosion.
- π Improper assembly after repair, such as forgotten screws or skewed board, will lead to poor contact.
- π Use of inappropriate parts, replacing the capacitor or fuse with a part with different parameters, is fraught with repeated failure.
One of the most insidious mistakes is the damage to the USB- connector, which is often soldered to thin board tracks, and if handled carelessly, they can break away, and if that happens, you can restore contact with thin wires and a soldering iron, but the process requires jewelry precision.
Another problem is the loss of the spring contacts that connect to the lighter, which are small and fall out easily when disassembled, so to avoid this, stick them to the lid with tape before opening the case or put them in a separate container immediately.
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If the charging doesn't work after repair, check the polarity of connecting the contacts to the lighter. Wrong polarity is a common cause of failure after self-repair.
When repairs are inappropriate: signs of hopeless breakdowns
Not all malfunctions of Xiaomi car chargers are repairable at home, here are the cases when it is better to buy a new device:
- π₯ The controller chip has burned, and replacing it requires specialized equipment and skills.
- π₯ The circuit board (cracks, detached tracks) is damaged, but repair is possible, but not reliable.
- π The transformer has failed. It's a serious breakdown, and it's going to cost almost the cost of a new charge.
- π‘οΈ The body is deformed from overheating. Even if the board is intact, it's not safe to operate.
If the charging stops after a power surge in the vehicle's on-board network (e.g., when you light a cigarette from another car), the varistor or stabilizer is likely to have burned, and these elements protect the circuit from overvoltage, but they themselves fail, and they can be replaced, but only with the exact analogue.
For example, if you need to buy a soldering station and consumables to replace the chip, it is easier to purchase a new charge. The prices for original Xiaomi devices start from 500 rubles, and repairs in the service can cost 1000-1500 rubles.
β οΈ Warning: If charging sparks when you connect to a lighter, stop using it immediately, which is a sign of a short circuit that could cause the car's wiring to catch fire.
Assembly and testing after repair
Once the fault is fixed, you need to properly assemble the charger and check its performance.
- Make sure all details are in place: board, contacts, screws (if any).
- Carefully lay the wires so that they do not clamped with the body.
- If the body has been glued, use a small amount of glue (e.g., B-7000).
- Connect the charger to the lighter and check the voltage with a multimeter. The USB output should be 5V Β± 0.2V.
- If the device detects charging as βslow,β check the resistance on the D+ and D- USB contacts (should be 2.7kΞ© for fast charging).
If the charging does not work after assembly, disassemble it again and check:
- π The quality of soldered joints is probably cold contact somewhere.
- π The polarity of connecting spring contacts to the board.
- π Track integrity - thin wires could have moved away when assembled.
If everything is fine but the charging still isn't functioning, there may be a problem in the vehicle's onboard network. check the voltage in the lighter - it should be in the range of 12-14.5V. If the voltage is below 11V or above 15V, the charging may be turned off for protection.
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To check the stability of the work, connect the charger to a powerful USB- tester (for example, Xiaomi USB Tester). It will show real current, voltage and power, which will help to identify hidden problems.