Disassembling the smartphone Xiaomi Redmi Note 9 Pro may be needed to replace the battery, repair the display, or clean dust. However, this process requires caution: incorrect actions can lead to damage to the cables, rupture of flexible cables, or even failure of the device. In this article you will find step by step instructions with photographs of key stages, a list of necessary tools and unique tips, which you will not find in standard manuals.

Model Redmi Note 9 Pro (codename joyeuse) differs from its predecessors in its reinforced design, but this does not mean that disassembly will become easier. For example, the back cover here is glued especially firmly - its removal without preheating almost always ends in cracks. We will tell you how to avoid common mistakes and maintain the tightness of the case after assembly.

Preparing for Disassembly: Tools and Safety Precautions

Before you begin, make sure you have everything you need. The absence of even one tool can turn disassembly into agony. Here minimum setwhich you will need:

  • 🔧 Plastic spatulas (2–3 pcs.) - for separating the lid and cables. Metal picks are not suitable: they scratch the body.
  • 🔥 Hair dryer or hot air station - to soften the glue. Optimal temperature: 60–70°C (no higher!).
  • 🧲 Magnetic mat or organizer — so as not to lose the screws (there are 15+ of them in different sizes!).
  • 🔋 Screen suction - will help raise the display after heating.
  • 🛠️ Screwdriver set: cross PH00, flat 1.5 mm, pentaradial Y00 (for some motherboard screws).

Also prepare your workplace: it should be clean, well lit and free of static electricity. Place a soft cloth (such as microfiber) on the table to avoid scratching the glass or metal parts. If this is your first time disassembling your phone, take a photo of each step - this will help with reassembly.

⚠️ Attention: Do not use a household hair dryer at maximum power! The hot air flow can melt the plastic latches inside the case. Keep the hair dryer at a distance of 10-15 cm and constantly move it to avoid local overheating.
📊 Have you disassembled smartphones before?
  • Yes, many times
  • 1–2 times
  • No, this is my first experience
  • I'm planning to try

Removing the Back Cover: Heating and Separating Technique

Back cover Redmi Note 9 Pro glued around the entire perimeter, and also has additional latches near the buttons and connector USB-C. To remove it, follow the algorithm:

  1. Turn off your phone and remove the SIM card tray.
  2. Stick on the screen protective film (for example, tape) so as not to scratch it with a spatula.
  3. Heat the back cover with a hairdryer in a circle for 2-3 minutes. Pay special attention to the corners - the glue is strongest there.
  4. Insert a plastic spatula into the gap between the cover and the housing (start at the bottom left corner where the antenna is located NFC).
  5. Gently run a spatula along the edge, gradually lifting the lid. If you feel resistance, heat the problem area again.

When the cover comes off, do not rush to remove it completely: it is connected to the body flexible fingerprint cable (if your model has a scanner on the back). Carefully disconnect the cable by prying it from the side with a spatula. B Redmi Note 9 Pro connector type is used FPC, which can be easily damaged if the wires are pulled!

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If the glue is too strong, use isopropyl alcohol (90%+). Apply a few drops into the gap between the lid and the body - it will dissolve the glue in 1-2 minutes without damaging the plastic.

Housing section Heating temperature Exposure time Notes
Bottom edge (connector USB-C) 65–70°C 30–40 sec The latches are located here - heat more thoroughly
Top edge (speaker) 60°C 20–25 sec Avoid overheating the microphone
Left/right corners 70°C 40–50 sec The glue here is the strongest
Center (logo Redmi) Do not heat! — There is no glue under the logo, but there are antenna lines

Disabling the battery: why is it critical?

Before touching the motherboard or cables, be sure to disconnect the battery. B Redmi Note 9 Pro A lithium polymer battery with a capacity of 5020 mAh, and even a minor short circuit can lead to it fire or bloating. Here's how to do it safely:

  1. After removing the back cover, you will see the battery - it is covered with a black film with a warning "Do not puncture!".
  2. Pry it up with a spatula orange connector (located next to the motherboard) and gently pull it up. Do not use force - if the connector does not budge, check that the glue is not holding it in place.
  3. After disconnecting, check the voltage at the battery contacts with a multimeter - it should be 0 V.

If the battery is swollen (this is noticeable by the deformation of the cover), do not try to pierce or bend it. In this case, it is better to contact a service center. A swollen battery can explode even from minor mechanical stress.

⚠️ Attention: In some batches Redmi Note 9 Pro (manufactured before June 2020) used a battery with defective charge controller. If, after disconnecting the connector, the battery shows voltage again, this is a sign of a malfunction and must be replaced.

Battery connector disconnected|Voltage checked with multimeter|Tools have no metal parts|No open flame or sparks nearby-->

Removing the Motherboard: Screws and Hidden Latches

Motherboard Redmi Note 9 Pro It is attached to the case with 15 screws of different types. Their locations and sizes are shown in the table below. Important: If you mix up the screws during assembly, you can damage the board or case!

Procedure:

  1. Unscrew all the screws, starting from the peripheral ones (in the corners) and ending with the central ones. Use a magnetic screwdriver to prevent the screws from falling inside the case.
  2. Carefully lift the board from the right side (the side of the volume buttons). Here she is held plastic latch - don't break it!
  3. Disconnect all cables:
    • 📱 Display (connector FPC-40P)
    • 🔊 Speaker and microphone (connector JST-6P)
    • 📶 Antenna cables (3 pcs., secured with clips)
Screw type Size Quantity Location
Cross PH00 3.5 mm 8 Along the perimeter of the board
Pentaradial Y00 2.5 mm 4 Around the battery connector
Flat 1.0 mm 2.0 mm 2 Under antenna modules
Cross PH000 4.0 mm 1 Under the vibration motor

After removing the board, inspect it for oxidation or burnt elements. Common problems Redmi Note 9 Pro:

  • 🔥CPU overheating Snapdragon 720G (visible by dark spots on the radiator).
  • 💧 Corrosion of contacts after exposure to moisture (even if the phone did not sink, condensation can accumulate under the screen).
  • 🔌 Detachment of soldered contacts of the connector USB-C (manifests itself as periodic shutdown of charging).

How to check the board for a short circuit?

Use the multimeter in "testing" mode. Connect the probes to earth (any metal screw on the board) and one by one to all connector pins. If the device makes a beep, this is a sign of a short circuit. In this case, the board must be cleaned or repaired by a service center.

Screen replacement: nuances and common mistakes

Display Redmi Note 9 Pro - one of the most vulnerable places. Replacing it requires not only accuracy, but also knowledge hidden fastenings. For example, the touchscreen cable here is glued to a metal frame, and it is easy to break if you pull it around a corner.

Step by step instructions:

  1. Heat the screen with a hairdryer (temperature 60°C) for 3-4 minutes. Start at the bottom edge where the train is located.
  2. Using a suction cup, lift the display 1–2 mm and insert the plastic spatula into the gap. Do not lift the screen completely - it is connected to the board two loops (display and touchscreen).
  3. Unscrew the metal plate covering the cable connectors (2 screws PH00).
  4. Disconnect the cables by pulling the black tabs on the connectors. Do not pull on the wires themselves!

When installing a new screen, please note:

  • 🔧 Frame mounting screws must be tightened with a force of no more than 0.3 Nm (tightening leads to glass cracks).
  • 🧴 The new display module comes without glue - use double-sided tape 3M 9448A or liquid glue LOCA (only for experienced craftsmen).
  • 🔄 After replacing the screen, you may need touchscreen calibration through the engineering menu (code *#*#6484#*#*).

⚠️ Attention: B Redmi Note 9 Pro used AMOLED display with integrated fingerprint scanner. If after replacement the screen does not respond to touch or the scanner does not work, check the connection flexible cable FPC — it could move during assembly.
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When purchasing a new screen, make sure it is compatible with your revision Redmi Note 9 Pro. Modules for versions joyeuse_global And joyeuse_in The cable connectors may differ!

Assembling a phone: how to avoid mistakes

Assembly is no less important stage than disassembly. Here's the main rule: work in reverse order, but taking into account the nuances:

  • 🔩 Tighten the screws criss-cross, starting from the central ones. This will prevent the board from warping.
  • 🧴 Before gluing the back cover, degrease the surface isopropyl alcohol. The adhesive does not adhere well to greasy or dusty surfaces.
  • 🔋 When connecting the battery, first connect the connector and then press the battery to the case. This will prevent the cable from bending.
  • 📶 Antenna cables must lie flat, without kinks. Otherwise the signal will deteriorate 4G/Wi-Fi.

After assembly, turn on the phone and check:

  • The functionality of all buttons (especially Power And Volume).
  • Touchscreen sensitivity around the edges (often suffers after screen replacement).
  • Charging via USB-C (if the phone does not charge, check the connector contacts).
  • The operation of the speakers and microphone (sometimes the audio cable is not connected tightly).

If your phone doesn't turn on after assembly, don't panic. Possible reasons:

  • Battery not connected (check connector).
  • Short circuit on the board (inspect for foreign screws or debris).
  • Damaged power cable (a common problem when removing the board carelessly).

Frequently asked questions (FAQ)

Is it possible to disassemble Redmi Note 9 Pro without a hairdryer?

Theoretically, yes, but the risk of damaging the cover or cables increases significantly. The glue in this model is very strong, and without heating the plastic may crack. An alternative is to use special solvent adhesive (For example, B-7000), but it may damage the antenna lines.

What glue is best to use for the back cover?

Optimal options:

  • Double-sided tape 3M 9448A - Easily removed during next disassembly.
  • Liquid glue LOCA UV - provides tightness, but requires UV lamps for polymerization.
  • Hot melt adhesive T-7000 - cheap, but can leave marks.

What should I do if the fingerprint scanner does not work after disassembling?

The reasons may be different:

  • The scanner cable is damaged (check the integrity of the wires).
  • The connector on the motherboard is not connected (inspect the contact FPC-Fingerprint).
  • The settings have gone wrong (reboot your phone and add your fingerprint again).

If the scanner is built into the screen, the problem may be incompatibility of the new display module.

How can I check if I damaged the board during disassembly?

Inspect the board for:

  • Darkened or swollen capacitors (a sign of overheating).
  • Scratches on tracks (may cause short circuit).
  • Peeled contacts (especially around the connector USB-C).

For accurate diagnostics, use a multimeter in resistance test mode.

How much does a professional disassembly service cost?

Prices vary depending on the region and type of work:

  • Battery replacement: RUB 1,500–2,500.
  • Screen replacement: 3,000–6,000 ₽ (depending on the originality of the spare part).
  • Board diagnostics: RUB 1,000–1,500.

Do-it-yourself disassembly is cheaper, but the risk of error is higher.