Owners of popular Xiaomi Redmi 3S and 3S Prime smartphones often face the need to physically access the internal components of the device. The main reason for opening the case is the failure of the battery, which eventually loses capacity.
This smartphone is designed in a sandwich, where the metal back cover is glued to the perimeter frame, which makes the dismantling process somewhat more complicated than devices with removable panels on the latches. The adhesive layer in Redmi 3S is strong enough, so it is critical to safely open the perimeter of the case, ignoring this step can lead to deformation of the metal or destruction of the glass insert.
Before you start, you need to prepare the workspace and tools, you need a dryer to heat the glue, a thin plastic card or a special mediator to open, and a set of screwdrivers. Remember that any manipulation of the hardware you do at your own risk, so act as carefully as possible.
Tools and workplace preparation required
Quality repairs start with proper preparation.To open the Xiaomi Redmi 3S without damaging the body, a conventional set of kitchen knives will not be enough. Professionals use a specialized tool that minimizes the risks of mechanical damage.
First of all, you need a heat source. A household hair dryer is good if it can heat the air to 80-100 degrees Celsius. More advanced masters use thermostoles or professional soldering hair dryers with temperature control. Also, a suction cup will be an indispensable tool to help create an initial gap between the lid and the frame.
- 🔥 Hair dryer construction or household (for heating the glue layer).
- 🛠 Set of screwdrivers (cross-haired) PH000 flat-to-unplug).
- 💳 Plastic card or mediator (metal instruments can close contacts).
- 🧲 Magnetic mat (so as not to lose tiny screws).
- 🧴 Isopropyl alcohol or liquid B-7000 (glue-removal).
Organize good lighting. Inside the smartphone are miniature plumes and connectors that are easily damaged by poor visibility. Make sure you have free space to place parts in order to remove them.
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Use a magnetic mat or a piece of paper squared to lay out the screws in the order you twisted them, which will help avoid problems when you build them, as the screws can have different thread lengths.
The procedure of heating the case and creating the first gap
The most critical step is to start dismantling, and if you try to slap the lid on a cold smartphone, the metal can bend and the glass can burst, and the heat softens the glue, making it elastic and allowing parts to be separated without undue effort.
Turn on the dryer and set the average temperature. Direct the hot air to the ends of the device. Move the dryer evenly around the perimeter, lingering at the corners and in the center for 20-30 seconds. Don't hold the dryer too close to overheat the display matrix or the battery.
⚠️ Warning: Don't heat the device too much.If the body gets too hot for the hand (over 60 degrees), pause.Overheating can damage the cameras' adhesive lenses or cause the battery to bloat.
After 2-3 minutes of warming up, try gently inserting a suction cup in the bottom of the back cover, retreating from the edge about 1-2 cm. Pull the suction cup up, creating tension, and simultaneously insert a plastic mediator into the resulting gap. If there is no gap, warm up a little more.
Dismantling the metal panel and disconnecting the plumes
Once you've managed to insert the mediator, start driving it along the perimeter of the housing, and the movements should be sliding, not stabbing, you'll hear the characteristic sound of the glue being cut, and go around the entire circuit until the back cover is free to move.
Take the metal panel off. Underneath it, you'll see a plastic insulating pad covering the main board and the battery, it's attached to several screws, and you'll need a small cross screwdriver to unscrew the fasteners.
The first step after removing the insulation plate is to turn off the device, find the battery plume connector and gently unplug it from the motherboard, and then you can safely touch the other components and turn off the display plumes or cameras.
- 🔌 Disconnect the battery plume first thing.
- 📱 Carefully remove the main display plume (wide connector).
- 📷 Turn off the front camera plume and proximity sensors.
- 🔊 Remove the lower board connector (for charging and microphone).
☑️ Safe disassembly
Battery replacement and glue cleaning
In the Xiaomi Redmi 3S, the battery is glued to the body with double-sided tape. You can't just pull it out. You can use a suction cup to extract the old battery or gently tamper with a plastic blade to avoid damaging the battery shell.
If you change the battery, make sure the new one has the same dimensions and voltage. The original capacity is 4100 mAh. Once the old element is removed, there will be a layer of old glue at the bottom of the case. It must be carefully removed using isopropyl alcohol and a plastic scraper.
The surface should be perfectly clean and fat-free before installing a new battery and sticking a new adhesive tape, which will ensure that the components inside the case are tight and securely fixed.
| Parameter | Original | Analogue | Chinese copy |
|---|---|---|---|
| Capacity | 4100mAh | 4000-4200 mic | 2500-3000 mAh |
| Tension. | 3.85 V | 3.85 V | 3.7 V |
| Weight. | ~95g | ~90-100g | ~60-70g |
| Jack | The right move | Coincides. | Oftentimes not the same. |
How to check the new battery?
Assembly of the device and restoration of leakage
The assembly process is done in reverse order: Install the new battery by pre-applying a special glue layer (e.g., B-7000) on the back wall or using a ready-made adhesive base. Press the battery and let the glue grip for 5-10 minutes.
Connect all the plumes back. Make sure each connector snaps with a characteristic light click. Lay down the insulating plastic plate and twist all the screws. Don't pull the screws over so you don't rip the threads off the plastic racks.
For the final fixation of the back cover, apply a thin layer of glue around the perimeter of the frame or use the ready-made adhesive tape for Xiaomi Redmi 3S. Tightly press the lid around the perimeter and lock the device with rubber bands for 15-20 minutes until completely dry.
⚠️ Warning: When assembly, make sure that the plumes are not clamped or twisted. Incorrect stacking of the display plume can cause spots on the screen or its complete failure.
Typical mistakes and expert advice
Often, beginners make mistakes that lead to additional breakdowns, one of the most common is the use of metal tools to slap the lid, metal can damage the graphite cooling layer or, worse, short the contacts on the board if the device was not completely de-energized.
Another mistake is ignoring the heat, and trying a syllog opening is guaranteed to cause the metal frame to bend, and then it's hard to align, and the phone can lose its moisture protection or start creaking when pressed.
- ❌ Do not use scissors or blades to pick inside the case.
- ❌ Do not connect the battery without making sure the connector position is correct.
- ❌ Do not leave the device on when the case is disassembled for a long time (risk of overheating).
If you feel like a piece is not being removed, don't use force. Check if all the screws are twisted and if the glue is warm enough. Patience is the master's main tool.
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The main secret of the successful dismantling of the Redmi 3S is the quality of the perimeter heating and the use of only plastic tools to separate the body.