How to remove the lid from Xiaomi Redmi 3S: full instructions

Xiaomi Redmi 3S has established itself as one of the most reliable budget devices of its time, but even such workhorses eventually need maintenance. Most often, users are faced with a broken screen, a worn-out battery or the desire to replace the rear panel with a fresher or different color. However, the design of this device involves a monolithic body, which makes the opening process quite difficult for the unprepared person.

The challenge is that the lid is not only attached to the screws, but also to a powerful adhesive layer around the perimeter. Unlike current models that use plastic latches, it requires heat treatment. Heating allows you to soften the adhesive composition, making it elastic and allowing you to separate the glass from the frame. Ignoring this stage is almost guaranteed to lead to chips or cracks on the back, turning a simple cosmetic repair into an expensive housing replacement.

Before you start dismantling, you need to prepare the workplace, it needs to be well lit and the surface of the table clean and free of foreign objects. It's also important to understand that the warranty on the device, if it's still valid, will be canceled after the seals are broken and the case is opened. If you're not sure about yourself, you better contact the service center, but for enthusiasts who want to do the repair themselves, this instruction will be an indispensable assistant.

⚠️ Warning: Before starting any work, be sure to completely turn off the smartphone. Attempting to remove the lid on the device on can lead to a short circuit if the plume is damaged or the battery is affected.

Tools and workplace preparation required

Quality repairs begin with the right tooling. For the Redmi 3S, a standard screwdriver and knife set will not be enough, or even dangerous. You will need a specialized tool that minimizes the risks of damage to internal components. Using inappropriate items such as kitchen knives or thick needles often results in the blade slipping and scratching the frame or, worse, piercing the lithium polymer battery.

Special attention should be paid to the source of heating. Professionals use separators or heat plates, but at home a temperature-adjusted building hair dryer or even a powerful household hair dryer is quite suitable, although the process will take longer. The heating temperature should not exceed 80-90 degrees Celsius, so as not to damage the display on the back side or melt plastic elements inside the case.

• 🔧 Screwdriver kit: A Phillips cross screwdriver #00 or #000 must be available for screws inside the case.
• 🌡️ Heat source: A hair dryer or heating pad to soften the glue under the back cover.
• 🎴 Plastic mediators: Thin plates for unscratched cover.
• 🧲 Magnetic mat: For sorting screws, as they may differ in length and threading.

Also, don't forget the suction cup. It's probably the most important element after the hair dryer. It's the suction cup that allows you to create the initial gap between the glass and the frame. If you don't have a special suction cup, you can use the suction cup from the phone holder to the car, pre-degrease the surface of the glass with alcohol for better grip. The degreaser will also come in handy at the end of the work to remove the residue of the old glue before installing the new panel.

⚠️ Warning: Never use metal blades (shavers, scalpels) to first open the Redmi body. 3S. High risk of damaging the fingerprint scanner plume that runs close to the edge of the glass.

Heating process and primary opening of the body

The most important step is to heat the back panel. Put the smartphone down on a soft, heat-resistant surface. Turn on the hair dryer and evenly heat the entire surface of the back cover, paying special attention to the edges. Movements should be circular, you can not hold the flow of hot air at one point for more than 2-3 seconds to avoid local overheating. The uniformity of heating is critical for the integrity of the glass.

The heating process usually takes 3 to 5 minutes depending on the power of your tool. Periodically check the temperature with your hand - the glass should become hot, but so that the finger can still tolerate touch (about 60 degrees). If the glass burns the skin instantly, then you overheat, and you need to let the device cool a little. Overheating can cause the battery to bloat or detach the polarizing film on the display.

After enough warming up, quickly but carefully place the suction cup in the bottom of the back cover, closer to the logo or slightly lower, but not at the very edge. Pull the suction cup up, creating tension, and insert a thin plastic mediator or a special spatula into the resulting microscopic gap. Don't try to plug the tool deep at once; your goal is simply to snap the glue at one point.

• 🔥 Temperature control: Heat the body to a point where it can barely be held in your hands.
• 👐 Tension technique: Constantly pull the suction cup upwards while introducing the mediator.
• 📏 Depth of Immersion: Do not enter the instrument deeper 3-4 mm to avoid damage to internal plumes.

Once the mediator has entered the glass, start slowly leading it along the perimeter, cutting the adhesive layer. The movements should be sliding, parallel to the plane of the phone. If you feel strong resistance, stop and warm up the area again. The force is not the assistant here; if the lid is not going, then the glue has not yet warmed up enough.

Dismantling the bottom panel and access to the battery

Once the back cover is successfully detached, you'll see the inside of the smartphone, but you can't take the battery or any other components out right away. At the bottom of the device, there's a plastic decorative bar covering the bottom end of the battery and speaker, and it's secured with a few screws and plastic latches, and the plastic is quite fragile, especially if the phone has been exposed to temperature changes.

First, you need to twist out all the visible screws that hold the bottom bar, usually about 10-12, and they can vary in length, and it's recommended that you put them on the magnetic mat in the same order you twisted them, or draw a layout. The order of the screws is important, because a screw that is too long, screwed into a short hole, can break the board or damage the thread.

Once the screws are removed, gently apply the plastic bar to the mediator, which is held on the latches that are located around the perimeter. Move from the edges to the center, sequentially clicking the locks. Don't put too much effort; if the bar is not removed, check if there is any hidden screw, often one of them can hide under the sticker or in the recess near the charging connector. Care at this stage will save the plastic from breaking.

⚠️ Attention: Under the lower plastic bar, there is a plume of the main speaker and the vibrator. When you disconnect the bar, act extremely carefully so as not to break the thin conductors.

Removal of the main board and disconnection of plumes

When the bottom is free, the battery and the bottom of the main board are accessed. However, to fully remove the lid (if this means a complete disassembly) or replace the screen, access to the top plumes is often required. In the Xiaomi Redmi 3S model, the main board is located at the top of the device and closed with a metal screen that is screwed.

The first thing you need to do is turn off the battery. The battery plume is under the metal plate at the bottom or connected to the side, depending on the board revision. Use a plastic blade to gently squeeze the connector out of the connector. Metal tools are strictly forbidden to use for this because of the risk of short circuit of the residual current.

Then you have to turn off all the plumes that go to the main board: the display plume, the touchscreen plume, the camera plumes and the side buttons. Each connector has its own fixing features: some just plug in the connector, others have an additional press bar that you need to bend. Remember the location of each plume or take a photo before you turn off. Photographing the assembly steps will greatly simplify the reverse process.

Once all communications are turned off, unscrew the screws holding the main board. There may be about 6-8 of them. Carefully raise the fee, checking if any hidden plume (such as an antenna wire or a button plume) is caught. The board is best removed, starting at the top edge where the headphone jack is located, if it does not interfere.

Battery replacement and device assembly

If the purpose of the disassembly was to replace the battery, now that access is open, you can remove the old battery. The battery in the Redmi 3S is glued to double-sided tape. Under no circumstances do not try to tamper with metal objects or bend it very strongly. Deformation of the lithium polymer battery can lead to its ignition or explosion.

For safe extraction, it is best to warm up the battery again a little (without the back cover already) or use special hoods with suction cups. If they are not available, you can use a thin but strong fishing line or dental floss. Stretching behind the battery and cutting the glue with sawing movements. This is the safest method, although it takes time.

Install the new battery in reverse order. In place of the old tape, apply special adhesive strips for batteries (B-7000 adhesives are better not to use, as it will complicate future repairs). Make sure the connector sits tightly in the connector. The entire device is assembled in reverse order: installing the board, connecting the plumes, installing the lower bar and screws.

• 🔋 Fixing: Use special adhesive strips, not superglue.
• 🔌 Connectors: When connecting the plumes, a slight click should be heard.
• 🧹 Clean: Before final assembly, remove all dust from the inside of the screen.

Typical errors and precautions

In the process of dismantling Xiaomi Redmi 3S beginners often make a number of standard errors that can cost the device life. One of the most common is the rush when peeling off the back cover. Users do not wait for enough warming and try to tear the glass by force, resulting in shattered glass. Another mistake is the loss of screws or entanglement of their seats, which leads to the inability to twist them back or, worse, damage to the thread in the plastic.

Another critical aspect is the plume, the fingerprint scanner plume in this model is very short and delicate, and if you take the lid off carelessly, it can be easily removed from the scanner board, it's almost impossible to restore it, and the fingerprint unlock function will stop working forever, and the plume requires delicate handling and the use of only plastic tools.

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Use isopropyl alcohol to remove residues of old glue. It does not conduct current and evaporates quickly, leaving no trace, unlike water or solvents.

And there's also static electricity, and although there's little risk, there's always a possibility that electronics will cause a static discharge that could knock out the chips, and it's advisable to work on an antistatic mat, or at least touch a grounded metal object periodically to take the charge off the body, and the safety of electronics depends on the little things.

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The key to success in dismantling the Redmi 3S is patience and sufficient glue heating. Don't force things if the part doesn't go.

Frequently Asked Questions (FAQ)