Disassembly Xiaomi Mi 9: detailed instructions with photos and nuances

The Xiaomi Mi 9, released in 2019, is still a popular smartphone due to its powerful hardware and affordable price in the secondary market. However, over time, even such a reliable device can require repairs from replacing the charging connector to recovering from a fall. Disassembling the Mi 9 is not an easy task: it includes a fragile glass case, adhesive battery fixation, and the risk of damaging the plumes when you carelessly move.

This article will help you disassemble your smartphone without consequences, even if you're doing it for the first time, and we'll go through every step from tool preparation to reassembling, point out pitfalls (for example, why detaching the battery plume should be the first step after opening the case), and give you tips on diagnosing malfunctions, and if you're in doubt, there's a checklist at the end of this article to check if you're ready for repair.

Preparation for disassembly: tools and security measures

Before you take on the screwdriver, make sure you have everything you need. Xiaomi Mi 9 is not a case where you can do anything: the wrong tools are almost guaranteed to lead to chips on the back or damage to the plumes.

Here is the minimum set you will need:

• 🔧 Plastic mediators (2-3 pieces) - for careful tweaking of the case.
• 🔥 A hair dryer or a thermo-air station to soften the glue under the back cover. Optimal temperature: 70-80°C.
• ⚡ Screwdriver. T3 and T5 — Use magnetic nozzles to keep the small parts from being lost.
• 🧲 Suction cups will help lift the lid after heating, and you'll want to take two, one for the top, one for the bottom.
• 🔋 Tweezers with curved ends - for working with plumes and small connectors.
• 📦 The screw container, so you don't mix them up when you build them, and you can even have an ice tray.

Also, prepare the workplace: it should be well lit, draft-free (so as not to blow away small parts) and with an antistatic mat (if any). Don't disassemble the smartphone on the carpet or the couch - static electricity can damage the motherboard.

⚠️ Warning: If you're disassembling a Mi 9 with a broken screen, be sure to put a tape on it before work begins.Splinters of glass can injure your hands or get inside the body, which will make repairs more difficult.

Step 1: Removing the back cover – how not to break the glass

The Xiaomi Mi 9's rear panel is glued all over the perimeter, and its fragility makes it difficult. The main mistake of beginners is to try to put the lid on cold. It almost always ends in cracks! So the first step is to soften the glue.

Turn on the dryer at average power and evenly warm the back of the smartphone for 2-3 minutes, paying special attention to the edges. The temperature should be comfortable for the hand (if the body burns, reduce heating).

1. Place the suction cup closer to the bottom edge (where the USB-C connector is).
2. Pull up with a slight effort - a gap should appear.
3. Insert a plastic mediator into the slot and gently run them around the perimeter, separating the lid.

If the lid doesn't lend itself, don't force it, warm up the problem area again. Most often, the camera and the top edge are more difficult, and when the lid is removed, put it in a safe place, it will come in handy.

Warm up the body with a hair dryer (70-80)°C)|Use a plastic mediator, not a metal|Start at the bottom edge (at the connector) USB-C)|Do not pull the lid sharply - only smoothly and evenly|Check if there is any glue left on the frame of the body-->

Step 2: Shutting down the battery – why it’s critical

Once the lid is removed, the first thing to do is to disconnect the battery, and it's not just a recommendation, it's a rule of thumb: if you accidentally close contacts on the board during a disassembly, the smartphone can fail without the possibility of recovery.

The battery in the Mi 9 is glued, but the power plume is on the right of it (if you look at the board).

1. Find a black connector with an orange tongue (this is the connector of the battery).
2. Carefully tuck the tongue with tweezers and pull up - the connector should come out of the nest.
3. Make sure the contacts are not closed (you can check with a multimeter if you have experience).

If the tongue breaks (this happens when you carelessly handle), do not panic. You can try to pull the connector with tweezers, tweezing it from the side, but do it very carefully so as not to damage the tracks on the board.

⚠️ Warning: If the smartphone still responds to the power button after the battery is turned off (for example, vibrates), then the power is not completely turned off. This may indicate a short circuit or a malfunction of the board.

Step 3: Removing the motherboard – working with plumes

The Mi 9 motherboard is mounted on 12 different size screws (don't confuse them when you build them!) but before you unscrew them, you need to unplug all the plumes.

• 📱 Display plume (the widest, at the top of the board).
• 🔊 Speaker plumes (two thin cables on the sides).
• 📷 Camera plumes (three thin connectors at the top).
• 🔋 The charger's tail (small, in the lower part).

To avoid damaging the plumes, don't pull them by the wires -- just the connectors! Use tweezers or plastic spatulas to gently lift the tongues. If the connector is "sticky," you can warm it up a little with a hairdryer (not above 60°C).

Once all the plumes are disconnected, unscrew the screws (better fold them in order on a sheet of paper with notes) and remove the board. Be careful: on its back, small parts, such as metal screens, may remain.

Replacement of the battery: nuances and errors

The battery in the Xiaomi Mi 9 is one of the most vulnerable parts, and over time it swells up, loses capacity or refuses to hold charge. Replacing the battery seems simple, but there are a few key points:

1. Check the new battery. Before installing, make sure that the voltage at the contacts of the new battery is 3.7-3.8 V (measured by a multimeter). If less, the battery is discharged and may not turn on.
2. Removal of old glue. Residues of glue under the battery must be removed with alcohol or a special cleaner. Do not use acetone, it can damage plastic parts.
3. Applying new glue. Double-sided tape or B-7000 liquid glue is good for fixing. Don't overdo it, excess glue can go on the board.

The most common mistake when replacing the battery is the wrong connection of the plume. If the smartphone does not turn on after assembly, check:

• 🔌 Is the battery connector correctly inserted (should click).
• 🔋 Are the contacts closed on the board (look for foreign particles).
• 📱 Does the display plume leave (sometimes it interferes with normal contact).

💡

If the battery is switched on after the battery is replaced but it's 0% charge, don't panic. Let it run for 10 to 15 minutes from the network, sometimes it takes time for the system to "see" the new battery.

Smartphone Assembly: How Not to Forget a Single Detail

Getting the Xiaomi Mi 9 back is often harder than disassembling, and the rule is to go backwards, but with nuances in mind:

1. Make sure all the plumes are connected to the end (click should be heard).
2. Check whether there are any foreign objects (screws, pieces of glue) inside the body.
3. When installing the back cover, first fix it with clips around the perimeter, and then warm up with a hair dryer for better gluing.

After assembly, be sure to test all the functions:

• 📞 Calls and microphones.
• 🔊 Dynamics (top and bottom).
• 📷 All three cameras (main, wide-angle, telephoto).
• 🔋 Charging (check both wired and wireless if supported).
• 🌡️ Approximation and illumination sensor (dial ##6484## in the dialer for the test).

If something doesn't work, don't panic. Maybe the train has just gone away. Take the phone apart again and check all the connections. If the problem persists, it's likely that the board or one of the modules is damaged.

💡

The most common cause of a broken display or camera after assembly is a misconnected or compressed plume, always check if it's curved or hit the board.

Typical malfunctions Xiaomi Mi 9 and their diagnosis

If you’ve taken apart a smartphone for repair, it’s helpful to know what problems are most common and how to identify them:

1. The touchscreen or display is not working.

Reasons:

• 💥 Display plume damaged (often in falls).
• 🔌 The board connector left.
• 💻 Video chip malfunction (requires rations).

Diagnostics: Connect the working display – if the image appears, the problem is in the screen or plume.

2. It's not charging.

Reasons:

• 🔌 Contaminated connector. USB-C (check for debris).
• 🔋 Failed charging controller on the board.
• 🔌 The connector plume is damaged.

Diagnostics: try charging from another cable/block. If it doesn't work, check the voltage on the battery contacts.

3. It's overheating.

Reasons:

• 🔥 Bloated battery (visually noticeable).
• 💻 Processor overload (check in Settings) → Battery).
• 🔌 Short circuit on board.

Diagnosis: if it warms up even when it is turned off, the problem is in the board or battery.

Frequently asked questions