How to disassemble Xiaomi Mi 9C NFC: a complete guide with photos and warnings

The Xiaomi Mi 9C NFC (codenamed crux), released in 2019, remains popular with users due to its balanced performance and support for contactless payments. However, over time, even reliable equipment requires repairs, from replacing the battery to cleaning the connectors or recovering from a fall. Disassembly of this device has its nuances – from the fragile plume of the fingerprint scanner to the adhesive mounting of the battery, which can not be detached by force.

In this guide, you will find a step-by-step photo instruction, a list of tools you need, and unique tips to prevent damage to flexible plumes, the most vulnerable part of the Mi 9C NFC. We will also analyze the typical errors that cause the device to stop turning on after disassembly, and give recommendations for choosing spare parts. If you have never disassembled Xiaomi smartphones before, start by preparing the workplace and carefully studying the structure of the case.

Preparation for disassembly: tools and security measures

Before you start, make sure you have everything you need. The Xiaomi Mi 9C NFC is not the most difficult disassembly machine, but without the right tools, the risk of damaging plastic latches or plumes increases dramatically.

• 🔧 Plastic mediators (2-3 pieces) - for separation of the back cover without scratches.
• 🔥 Dryer or thermo-air station - for softening the glue (temperature 60-80)°C).
• ⚡ Suction cup - helps to lid after heating.
• 🔩 Sets of screwdrivers: cross PH00 and five-point Y00 (for screws under the back cover).
• 🧲 Magnetic mat or container – to avoid losing small details.
• 📱 Tweezers for working with plumes and connectors.

Important: The Mi 9C NFC has an adhesive battery, so it will require a 90%+ isopropyl alcohol (to dissolve the glue) and a plastic spatula (a metal blade can puncture the battery!). If you are planning a screen replacement, additionally prepare a two-way tape to fix the new display.

⚠️ Warning: Do not use metal tools to separate the back cover — even a small scratch on the antenna tracks (located around the perimeter of the housing) can degrade the signal NFC, Wi-Fi or 4G.

Before disassembly it is necessary:

1. Turn off your smartphone and remove it. SIM-map.
2. Discharge the battery to 20-30% – this will reduce the risk of fire in case of accidental damage.
3. Make a backup of the data (disassembly may result in resetting settings).

Removal of the back cover: technique and typical errors

The back of the Mi 9C NFC is mounted on latches and glue, and the challenge is not to damage the plastic clamps that break under excessive pressure.

1. Direct the hair dryer to the edge of the cover (from the side of the switching button) at a distance of 5-7 cm.
2. Heat each corner for 30 seconds, then move along the seams.
3. Apply the suction cup to the bottom edge (near the USB-C connector) and pull up.
4. Insert a plastic mediator into the resulting gap and carefully guide it around the perimeter.

If the lid doesn't lend itself, don't increase the force, you better reheat the problem area.

• 🔴 Overheating – temperatures above 80°C deform plastic.
• 🔴 Using a knife – metal will cut through antenna tracks.
• 🔴 Sharp motion - the latches break when jerking.

After removing the cover, you will see:

• 📋 Battery with connected plume.
• 📋 A motherboard closed with a metal screen.
• 📋 Fingerprint scanner (built into the power button).
• 📋 Dynamic and vibrator (lower part).

Battery shutdown: why it's critical

Before touching the motherboard or plumes, be sure to turn off the battery. In the Mi 9C NFC, it is connected via a JST 1.0 connector (white) next to the top edge of the board. Use a plastic blade to gently lift the connector:

If you skip this step, the risks are:

• 💥 Short circuit when the screwdriver touches the components of the board.
• 🔋 Damage to the power controller (resulting in no charging).
• 📱 Automatic activation when pressing the power button during disassembly.

After turning off the battery, check the voltage on the contacts of the board with a multimeter (should be 0 V). If there is a voltage, then there is a connection somewhere (for example, the display plume can supply power to some circuits).

⚠️ Warning: In Mi 9C NFC, the fingerprint scanner plume runs under the battery, so if you're planning to replace it, turn off the plume before the battery is removed, or you risk breaking the contacts.

Battery recovery: methods and risks

The battery in the Mi 9C NFC is glued to the body, and improper removal is the main cause of fires or bloating during later use.

Recommended algorithm:

1. Apply alcohol around the perimeter of the battery (do not pour on the board!).
2. Wait 5 minutes, then gently tuck the battery with a plastic spatula.
3. If the glue does not respond, repeat the procedure, increasing the time of exposure to alcohol.

After removal, inspect the battery for swelling or damage to the shell. If the battery is deformed, it cannot be re-mounted, replace it with a new one (original article: MB-CRUX-BAT-30).

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If the battery is particularly glued, try combining methods: first heat the hair dryer (1 minute), then apply the alcohol.

Disassembly of motherboard and plumes

The Mi 9C NFC motherboard is fixed with 12 screws of different sizes, and remember their location, you can't confuse the screws when you build them!

Procedure for disconnecting the plumes:

1. Display - a wide plume in the lower part of the board (fixed with a latch).
2. The main camera is a thin plume next to the upper edge.
3. The fingerprint scanner is a small connector under the battery.
4. Additional modules (vibromotor, speaker) - are turned off last.

When working with plumes:

• 🖐️ Only take the black plastic parts, don't pull the gold contacts.
• 🔍 Use a magnifying glass if you can't see the latches well.
• 📸 Take a photo of each stage, which will help with the reverse assembly.

⚠️ Warning: In the Mi 9C NFC, the fingerprint scanner plume is extremely fragile. If it breaks, the switch will stop working, and fingerprint unlocking will become impossible. Replacing the plume requires soldering and costs ~1,500 rubles.

After you have removed the fee, examine it for:

• 🔥 Darkening is a sign of overheating of components.
• 💧 Oxidation - especially around the USB-C connector (indicates moisture intrusion).
• 🕳️ Cracks - often occur after falls.

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If the board has visible damage, do not turn on the smartphone until the diagnosis at the service center.

Replacement of components: what can be done on your own

In Xiaomi Mi 9C NFC, the user can replace the following details (if you have experience):

When replacing the display, note:

• 📱 The new screen may not have pre-applied adhesive — double-sided tape is required 3M.
• 🔧 After replacement, be sure to check the touchscreen before final assembly.
• 💡 The brightness and color reproduction may differ from the original (especially for non-original panels).

If you need to replace the charging connector or microphone, be prepared to solder — these components are soldered to the board. Without experience, it is better to contact the service, as sloppy soldering can damage the tracks.

Assembly and performance check

The Mi 9C NFC should be assembled in reverse order, but with a few nuances in mind:

1. Before installing the battery, clean the contact board with alcohol.
2. Make sure that all the plumes are tightly fixed in the connectors (the click should be heard).
3. Twisting the screws cross-cross to avoid skewing the board.
4. Before fixing the back cover, check the operation of all buttons and sensors.

After assembly, perform the test:

1. Turn on your smartphone and check the charging (plug the cable).
2. Test the camera, speaker and microphone.
3. Make sure the NFC works (try paying for something).
4. Check the fingerprint scanner and vibrator.

If something's not working:

• 🔍 Recheck the connection of the plumes - often the problem is poor contact.
• 🔧 Check the charge for damage (especially if the smartphone is not turned on).
• 📱 Reset settings (if sensor or camera issues)

⚠️ Warning: If the smartphone overheats or runs out quickly after assembly, it's likely that the battery is not connected correctly or damaged. Disable it immediately and check the contacts.

FAQ: Frequent questions about the dismantling of Xiaomi Mi 9C NFC