Disassembly of the Xiaomi PB200LZM powerbank: a step-by-step guide

The Xiaomi PB200LZM series’ external batteries have proven to be reliable, high-capacity devices, but even high-quality electronics can require maintenance over time. Most often, users are faced with the need to replace worn-out lithium polymer cells or repair the board of a controller that has stopped correctly controlling charge currents. Disassembling this device is a delicate process that requires not only the right tool, but also an understanding of the internal architecture of the gadget.

The paverban is designed as a monoblock, where the main body is the framework for all components. The aluminum body not only protects the insides from mechanical damage, but also acts as a radiator, removing heat from the control board during intensive work. This feature makes the opening process more difficult compared to plastic counterparts, as it requires careful handling of latches and adhesives so as not to damage the appearance of the device.

Before you start dismantling, it is important to realize that any interference with the design will automatically void the manufacturer's warranty. If your device is still in warranty service, it is wiser to contact an authorized service center. However, if the warranty period has expired and the battery has lost a significant part of its capacity, self-replacement of the elements can give the power bank a second life, returning to its declared power of 20,000 mAh.

Tools and workplace preparation required

The success of the disassembly operation depends on 80% on the quality of preparation and the availability of a specialized tool. To work with the Xiaomi PB200LZM, you will need a set of precision screwdrivers, since screws in these devices usually have custom hats. Most often, screws with Torx T5 or T6 slits are used, which cannot be twisted with a regular cross screwdriver without the risk of tearing the thread.

In addition to screwdrivers, tools are critical to safely open the body without damaging metal. Plastic mediators or blades will help to snap the locks without leaving scratches on glossy surfaces. Metal tools such as thin blades or needles should be used with extreme caution to avoid accidentally damaging lithium polymer cells, the puncture of which can lead to fire or explosion.

⚠️ Before starting any work, make sure that the powerbank is completely discharged or, conversely, has a charge of about 50%.Working with a fully charged battery increases the risk of short circuits in case of accidental damage to the insulation of the wires.

The organization of the workspace also plays an important role. You will need good lighting and, preferably, a magnetic mat or a container with cells for sorting screws. The screws in Xiaomi can differ in length and diameter at different points of attachment, and by confusing them during assembly, you can damage the threads in the plastic housings or even break through the insulation of internal components.

• 🛠️ A set of precision screwdrivers (required the presence of Torx bits) T5/T6)
• 🔧 Plastic blades and mediators for opening the body
• 🔦 Powerful flashlight or lamp for illuminating internal components
• 🧤 Antistatic gloves to protect electronics from static electricity

Algorithm opening the case Xiaomi PB200LZM

The opening process begins with a close inspection of the perimeter of the device. The PB200LZM often lacks visible screws on the outside, as the main fastener is hidden under decorative linings or rubber legs. Carefully probe the ends and back panel: if you find rubber anti-slip linings, they must be carefully removed by poking a thin blade or needle.

Under the stripped pads, the screws usually hide that hold one of the halves of the body. After they are unscrewed, don't immediately try to push the halves apart. Inside, there are plastic latches that hold the structure together. Use a thin plastic blade to put it into the joint between the aluminum frame and the plastic base, and carefully guide along the perimeter, hearing the characteristic clicks of the snapping fixtures.

Special attention should be paid to the plumes and wires connecting the halves of the case. In some Xiaomi revisions, the on button or charge indicators can be soldered on a board located in one part of the case and connected to the main board with thin wires. A sharp extension of the halves without visual control can lead to the breakdown of these connections, the restoration of which will require soldering skills.

• 🔍 Carefully inspect the perimeter for hidden screws under the stickers
• 👐 Use only plastic tools to separate the body
• ⚡ Do not make sudden movements until you are sure that there are no connections between the halves.

Dismantling of battery cells and control boards

Once the lid is successfully removed, you will see the inner device of the power bank, which is mostly four rectangular batteries connected in series and parallel. The PB200LZM typically uses 18650 cells or flat Li-Pol bags, depending on the year of release and the specific modification, which are tightly packed and fixed by shrinkage or plastic frame.

The control board, which is responsible for charging, discharging and protecting, is usually located on top or side of the battery pack. It is attached by screws to the plastic base of the housing. To extract it, you need to disconnect the balance connectors and power wires. Be extremely careful: the connectors can be quite tight, and with excessive force, it is easy to tear them out with the root along with the pieces of textolite.

If you want to replace batteries, you'll need a multimeter to check the voltage on each cell. Often only one or two cells fail while the rest remain functional. However, to keep the BMS running, you'd better change the entire set at once using cells with the same internal resistance and capacity.

• 🔋 Check the voltage of each cell before dismantling
• 🔌 Disconnect the connectors gently, holding onto the plastic part of the connector
• 🌡️ Avoid overheating batteries when soldering new contacts

Diagnostics of faults and replacement of components

The most common problem with old power banks is the bloating of batteries or loss of capacity. If the device has stopped holding charge or warms up when working, first of all suspect chemical sources of current. However, if the power bank does not turn on at all or does not charge, the problem may lie in the failure of the power controller or MOSFET-transistors.

Visual inspection of the board often helps to identify burnt components. Look for blackness, bloated capacitors or chips on chips. A deeper diagnosis will require a device diagram that is difficult to find for Xiaomi, but the principle of operation is similar for all power banks. Checking the chains for short circuit with a multimeter in vertebrae mode is the first step to identifying a faulty node.

Polarity is important when replacing batteries. An error in the connection of the "+" and "-" will lead to instant failure of the controller board, and in the worst case, to thermal acceleration of the batteries. New cells should be charged to the same voltage (about 3.7-3.8 V) before installation, so that the balancing system works correctly from the beginning.

⚠️ Warning: Never close battery contacts with metal objects. Short circuit of the lithium-polymer cell causes instant warming to temperatures that can ignite clothing or melt the tool.

Assembly of the device and check of performance

The assembly process is reversed. Put the battery pack in place, making sure the wires are not clamped and are in the designated channels. Tighten the control board by checking for screw holes to match. Excessive force when tightening the screws on the plastic case is unacceptable, it can lead to cracks that will disrupt the sealability and aesthetics of the device.

Before you finally lock the lid, do a primary test, connect the powerbank to the charger and check if the charge indicator lights up. Then plug in the load (like a smartphone) and make sure the device is giving off current. If all the steps are successful, you can gently snap the body around the perimeter, starting at one of the corners.

💡

When assembling the case, use a minimum amount of glue, enough drops in the corners or use double-sided tape, so that in the case of the next disassembly, you do not have to use brute force.

The final step is to install decorative pads and rubber legs. Make sure all screws are twisted and don't hang. A properly assembled Xiaomi PB200LZM should not make any extraneous noise when shaken. If you hear rattles, then some screw is not twisted or the component is poorly fixed inside.

💡

The main rule of assembly is not to force events, and if the part does not fall into place, then you are doing something wrong or forgot to unscrew the hidden screw.

Frequently Asked Questions (FAQ)