The Redmi 7A series, codenamed the Xiaomi M1804C3CG, has proven to be reliable budget devices, but over time even they require intervention. Owners often face the need to replace the battery, clean the speakers or recover from moisture. However, before starting repairs, it is important to clearly understand how to properly and safely open the cover of this device so as not to damage fragile plastic and internal plumes.
The body design in this model involves the use of perimeter adhesives, which makes the dismantling process more complex than the collapsible smartphones of the past. A sloppy autopsy can lead to chips, cracks in the frame or, worse, damage to internal components. In this article, we will discuss in detail the entire process, the necessary tools and nuances that are silent in service centers.
Before you start, make sure you have enough time and a calm environment, and rushing is the enemy, because one wrong move by the tool can cost you the integrity of the display or body. We'll look at the steps from preparation to final assembly, focusing on heating the edges of the case to 80-90 degrees, which is critical for successful peeling off the rear panel.
Tools and workplace preparation required
Good workplace preparation is the foundation of a successful renovation, and you're going to need not only a toolkit, but a well-organized space where nothing gets lost or falls, and the lighting needs to be bright, without flickering, so you can see the smallest details and screws.
The M1804C3CG is characterized by the use of screws with T5 and T6 slits, so a regular cross screwdriver will not work here. It is also critical to use a suction cup or a special plastic opener to avoid damaging the glossy surface of the back cover. Metal objects are better kept away from the work area while working with the battery.
- 🔧 Set of screwdrivers with interchangeable nozzles (required presence of Torx) T5 and T6)
- 🌡️ Hair dryer (building or household with temperature adjustment) or heat pad
- 💳 Plastic card or mediator for snapping latches
- 🧲 Magnetic mat or screw sorting tray
- 🧴 Isopropyl alcohol or special liquid B-7000 reassemble
Don't forget to turn off the device before you start any manipulations. If your smartphone doesn't turn on because of software problems, try to drain the battery to a minimum to reduce the risk of short circuits if the contacts are accidentally damaged. Safety is the number one priority when working with lithium-ion power sources.
☑️ Checking readiness for autopsy
Technique of safe heating of the body
A key step in the process of opening the Xiaomi M1804C3CG cover is softening the factory adhesive. Manufacturers use a heat-resistant compound that keeps the body dead at room temperature. Heating is needed to make the adhesive elastic and allow the tool to penetrate the joint.
Use a dryer by setting the temperature around 80-90 degrees Celsius. Don't keep the hot air flow at one point for too long to overheat the display matrix or plastic frame elements. Move the hair dryer around the perimeter of the device, paying special attention to the corners where the glue is usually the most.
⚠️ Warning: Never heat the device above 100 degrees, as this can cause the battery to bloat or deform the internal plastic frames, making subsequent assembly impossible.
Check the glue's readiness to open carefully. After 2-3 minutes of warming up, try to press the suction cup slightly and pull. If the lid does not lend itself, continue heating, but take breaks, letting the body cool so as not to overheat it. Patience is more important than strength.
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To check if the glue is warm enough, gently touch the edge of the back cover with your finger - it should be hot but tolerant to touch (about 60-70 degrees on the surface).
Rear detachment process
Once the body is warm enough, the most critical moment is that you need a suction cup that you need to attach to the bottom of the back cover, closer to the center, but not too close to the camera module. Create tension by lifting the lid, and simultaneously inject a thin plastic tool or mediator into the resulting gap.
Move slowly around the perimeter. Inside the Redmi 7A housing are plumes that go to the side buttons and the main module, so the tool should not dive more than 2-3 millimeters. Sharp movements can lead to a break in thin conductors.
- 📱 Start at the bottom end where there are usually no plumes.
- 🔄 Move up the side edges, gradually cutting off the glue
- 🚫 Avoid the area at the top where the camera and flash are located.
- 🛠️ Use a thin metal blade only if the plastic is not coping, but with extreme caution.
If you feel a lot of resistance, don't push harder. Go back to the heat. Often users make the mistake of trying to force the panel to pull back, which causes cracks in the glass of the back cover. The adhesive layer has to move out evenly.
What to do if the lid is cracked?
Disconnecting plumes and access to the insides
When the back cover is removed, you have access to the internal components, but before touching the board, you need to turn off the battery. In the M1804C3CG, the battery connector is under a protective plastic bar that is screwed.
Use a T5 or T6 screwdriver to unscrew the screws that lock the motherboard's metal or plastic protection. Act carefully, the screws can be of different lengths, so remember or unfold them in order of twisting. Once the protection is removed, you will see a wide battery plume.
To turn off the plume, use a plastic shoulder blade or nail. Metal tools can cause a short circuit if you accidentally hit other contacts on the board. With a light upward movement, you can put the connector in, it should come out of the groove without undue effort.
| Component | Type of attachment | Tool. | Risk of damage |
|---|---|---|---|
| Back cover. | Clay. | Fryer, sucker. | Tall (cracks) |
| Protective bar. | Torx screws | Screwdriver T5/T6 | Medium (cut edges) |
| AKB slack | Clamp (connector) | Plastic/Toenail | High (contact break) |
| Camera module | Clay/Paz | Tweezers | Critical (lens scratches) |
Only after the battery is turned off can you safely carry out further manipulations: changing the speaker, vibrator motor or cleaning the connectors. The electronic board of the smartphone is very sensitive to static electricity, so try not to touch the contacts with your hands.
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Always first turn off the battery plume before disconnecting any other plumes (screen, cameras, boards) to avoid short circuit and burnout of the power controller.
Typical errors in disassembly of Xiaomi M1804C3CG
Even experienced craftsmen sometimes make mistakes, let alone beginners, and one of the most common problems is that the plume of the main camera module, which runs very close to the edge of the case, is damaged when the opener is not sloppy, and then the camera stops focusing or producing an image.
Another common mistake is the loss of screws: The Xiaomi M1804C3CG uses different length screws for different nodes. If you twist a long screw into the hole for a short one, you can punch the board or rest on the components, which will lead to a break in the case when tightened.
- ❌ Ignoring heating and trying to remove the cover on the cold"
- ❌ Using a knife instead of a plastic card to open
- ❌ Disconnection of plumes under tension, without first removing protection
- ❌ Attempting to bend the battery to extract it (fire risk)
⚠️ Attention: It is strictly forbidden to puncture or bend the battery. If the battery is swelled and interferes with the extraction, use isopropyl alcohol to dissolve the glue underneath, but do not use physical force.
Be careful of the small details. For example, under the volume and on buttons are often rubber pads or plastic pushers. When you remove the lid, they can stick to it and fall out. Save all the small elements, without them, the buttons will not work properly.
Assembly and seal check
The assembly process is a mirror image of the disassembly, but it has its own nuances: before installing the back cover, remove the residue of old glue from the frame and the cover itself, use isopropyl alcohol and soft fabric to clean the surfaces.
To fix, use a special glue sealant (for example, B-7000) or bilateral tape, pre-cut around the perimeter. Apply the glue with a thin strip, avoiding hitting the camera and speaker. After gluing the lid, it is recommended to fix the smartphone with rubber bands for 15-20 minutes for primary polymerization.
Remember to plug in the battery and check the touchscreen, sound and vibration before the final sticker. If everything is working correctly, you can complete the assembly. The tightness in budget models is lost after opening, so you don't have to count on water protection in the future.
Check the density of all the elements. There should be no gaps. If the lid is coming out, you may have not cleaned the old glue well or used too much new compound, in which case you will have to repeat the procedure.