Xiaomi Redmi 3S has proven to be a reliable device with excellent value for money, but even the most durable equipment is subject to wear and tear or accidental damage. Broken display, bloated battery or faulty charging connector are typical problems that require intervention inside the case. Self-disassembly can save a significant amount on the services of the service center, if you perform all the actions carefully and consistently.
Before starting work, you need to prepare a workspace with good lighting and stock up on the necessary tools. The process of dismantling the Redmi 3S requires care, as inside are thin plumes and fragile connections, damage to which can lead to complete inoperability of the gadget. In this article, we will look at each step in detail so that you can safely perform repairs.
Tools and workplace preparation required
The success of the operation depends on the quality of preparation. You will need a minimum set of tools that can be found in any specialized radio store or ordered online.
First of all, get a set of screwdrivers, where there are necessarily bits Torx (star) and Phillips (cross). To work with small screws inside the smartphone, the size of the PH00 or PH000 is suitable. Also critical is a mediator or plastic blade for opening the case without scratches.
- 🔧 A set of precision screwdrivers with magnetic tips.
- 🔥 A hair dryer or thermophen to heat up adhesive base.
- 🧲 Magnetic mat for sorting screws by disassembly stages.
- 📷 Smartphone or camera for photofixing assembly stages.
Pay special attention to the cleanliness of the table surface. Small screws can easily get lost in the pile of the carpet or roll to the floor. Using a magnetic mat will allow you to spread the screws in order of their extraction, which will greatly simplify reverse assembly.
⚠️ Warning: Before you start any work, be sure to turn off the device completely. If the screen is broken but responds to touch, turn off the smartphone programmatically. If the display does not work, press the power button on the device. 10-15 seconds before vibration.
Removal of the back cover and primary dismantling
The Xiaomi Redmi 3S design involves a plastic back cover that is mounted on perimeter latches and two screws at the bottom, starting with removing these screws hidden under plugs or visible at the bottom of the body next to the charging connector.
After the screws are twisted, you need to warm up the perimeter of the lid. The glue softens at a temperature of about 60-70 degrees Celsius, so you should not overheat the body so as not to deform the plastic. Keep the hair dryer at a distance of 5-7 cm, moving it evenly along the seam for 2-3 minutes.
How do you know if the glue is warm enough?
To snap, use a thin mediator, insert it into the junction between the frame and the lid. Lead the tool in a circle, gradually releasing the latches. Don't put excessive effort at one point - it is better to go in a circle several times, gradually increasing the gap.
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If the back cover is difficult to remove, do not pull it by force. It is better to warm up the problem area with a hair dryer once again, since the plastic can crack when jerking.
Disabling the plumes and retrieving the battery
Once the lid is removed, you will see the internal layout of the device, and the first step is always to disconnect the battery plume from the motherboard, a mandatory safety procedure that prevents short circuits from further working with electronics.
The battery plume in the Redmi 3S is connected at the bottom of the board. Carefully tuck the connector with a plastic blade as you move from edge to center. Do not use metal objects under any circumstances so as not to damage the contact paths on the board.
Next, you unscrew the metal shield that covers the main connectors of the display and touchscreen, which is usually secured by several screws of different sizes, and remember the location of each screw, as they may differ in length and thread.
☑️ Safe disabling of components
Once the metal shield is removed, you can disconnect the plumes of the display and touchscreen, and they can be pressed by a connector that needs to be gently bent upwards, and now the main module is free, and you can start removing the battery if repairs require it.
Dismantling the main board and camera module
Xiaomi's main board is secured by perimeter screws and is held on plastic guides. Before extracting, make sure all plumes are turned off, including the antenna wire, which is often fastened by a latch.
An antenna cable (coaxial wire) usually passes through special slots in the case, it must be carefully snapped from the main connector, pulling up the metal tip, not the wire itself, damage to the insulation of the wire will lead to loss of the network signal.
Removing the board requires care. Lift it from one edge, check if any element is caught, and smoothly remove it from the housing. Notice the location of the vibrator and lower speaker, which can also be mounted on or near the board.
The main camera module in this model is embedded in the board or connected with a separate plume, depending on the revision. If the camera is separate, its plume passes under metal screens, so you need maximum accuracy when removing it.
⚠️ Warning: Avoid static electricity when working with the main board; it is advisable to use an antistatic bracelet or periodically touch the grounded metal object before touching the electronics.
Replacement of the display and touch screen
The most common reason for disassembly is to replace a broken screen. In Redmi 3S, the display module is often assembled with a frame, which makes it much easier to replace. You don't have to peel off the old screen, you just need to move the internal components to a new frame.
If you have a frameless module, the process is complicated by the need to clean the old glue and position the new glass accurately, in which case it is recommended to use a special glue B-7000 or double-sided tape for electronics.
Install the new module in the case, after running the plumes through the technological holes, connect the plumes to the motherboard until the final fixation of the screen to check its performance.
The check includes turning on the smartphone, checking the matrix for broken pixels and testing the touchscreen for dead zones, and only after making sure that it is working, you can start the final assembly.
Table of the main screws and their location
For ease of assembly and design understanding, below is a table with the main types of screws used in the Xiaomi Redmi 3S. The length differences can be critical, so follow this scheme.
| Location. | Type of screw | Size | Number of |
|---|---|---|---|
| Back cover (bottom) | Phillips (cross) | 2.5 mm | 2 pcs. |
| Protective board (metal) | Phillips (cross) | 3.0 mm | 4-5 pcs. |
| Fixing fees | Phillips (cross) | 2.0 mm | 2 pcs. |
| Down speaker | Phillips (cross) | 2.5 mm | 2 pcs. |
Assembly of the device and verification of functionality
You do the reverse assembly. Start by putting the battery in and connecting the plume. Make sure the connector is up straight before you click. Then you put the metal safety plate in and you twist all the screws.
Turn on your smartphone without sticking the back cover to run the final test of all the features: sound, vibration, cameras and proximity sensor. If everything works correctly, apply a new glue or double-sided tape around the perimeter of the case.
Press the back cover and hold it with rubber bands for 15-20 minutes until the glue is completely dry. Don't turn on the device immediately after assembly, let the materials grab.
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Quality assembly depends not only on the correctness of actions, but also on the time allocated for the polymerization of the glue and the accuracy of the installation of plumes.