Disassembly of the Xiaomi Mi TV 4S remote: from latches to the printed circuit board

Why Xiaomi Mi TV 4S remote may require disassembly

Remote controls from Xiaomi Mi TV 4S (L43M5-5AIN, L50M5-5AIN, and others) are known for their reliability, but even they fail over time. Most often, users experience button sticking, sensor failure or loss of communication with the TV. The causes may lie in dust, fluid intake, battery discharge or wear of contacts. Disassembly of the remote is the first step to diagnosis and repair.

It's important to understand that the design of the Mi TV 4S remote is different from the classic IR remote, using Bluetooth connectivity and a touchpad instead of mechanical buttons. This puts restrictions on disassembly techniques. For example, applying brute force to the latches can damage the flexible plume of the sensor, which will make the remote irrepairable. In this article, step-by-step analysis with the characteristics of the model.

Preparation: Tools and precautions

Before you start dismantling, prepare the workspace and tools.

• 🔧 Plastic mediator (or guitar) - to disconnect the latches without scratches.
• 🔨 Thin screwdriver (cross, 1.5-2 mm) - for screws inside the body.
• 🧲 Magnetic mat or container – to avoid losing small details.
• 📸 Smartphone - for photographing the dismantling stages (useful when assembly).
• 🧴 Isopropyl alcohol (90%+) Cotton swabs - to clean contacts.

Also consider:

• 🚫 Do not use metal tools to separate the body - they leave traces.
• 🔋 Remove the battery. CR2032 before disassembly to avoid short circuit.
• 🧤 Work with gloves if you plan to clean with alcohol – it dries your skin.

⚠️ Warning: If the remote was in high humidity (e.g. in the bathroom), dry it in rice or silica gel for at least 24 hours before disassembling.

Step 1: Removing the back cover of the remote

The body of the Mi TV 4S is made up of two parts, which are held together by plastic latches, and the main difficulty is that they are arranged with 4 latches on the sides and 2 hidden under the battery compartment to remove the lid.

1. Make sure the battery is removed.
2. Insert a plastic mediator into the gap between the front and rear panels at the battery compartment.
3. Carefully drive the mediator along the seam, alternately snapping the mounts, starting at the OK side.
4. When all the latches open, remove the back cover without making any effort - a flexible plume may be glued inside.

If the lid doesn't lend itself, don't try to pull it out. You probably missed the latch. Look at the lid for a lumen, sometimes you can see them.

Step 2: Disconnect the flexible sensor plume

Once you remove the lid, you'll see a PCB with a soldered Bluetooth module and a flexible plume connecting the touchpad to the board, which is the most vulnerable area of the remote, and if it's damaged, it will cause the sensor to fail.

To disconnect the plume:

1. Carefully tuck the black lock connector (it looks like a small latch).
2. After clicking, the lock will rise, and the plume can be removed by pulling up.
3. Do not pull the plume itself - take on the hard part of the connector.

⚠️ Warning: If the plume is glued to the body with tape, do not tear it sharply. Warm the place with a dryer duct tape (temperature not higher than 50).°C) to soften the glue.

Step 3: Printed circuit board extraction and diagnosis

Once the plume is detached, you can remove the circuit board, which is attached to the body with two Torx T3 screws (less commonly, Phillips 00), unscrew them and gently raise the board without pulling the wires.

Now you can make a diagnosis:

• 🔍 Visual inspection: Look for blackened or bloated elements (capacitors, resistors).
• 💧 Corrosion traces: Green plaque on contacts indicates moisture.
• 🔋 Battery Contacts: Oxidation on spring contacts is a common cause of unstable operation.

If the problem is oxidation, clean the contacts with a cotton swab dipped in isopropyl alcohol. Use an eraser or a special contact cleaner liquid to remove corrosion.

💡

If the remote doesn't respond to pressing, but the button lighting is working, the problem is probably the sensor plume.

Comparison of faults and repair methods

Remote Assembly: reverse order and testing

The Mi TV 4S remote is assembled in reverse order, but taking into account the nuances:

1. Set the printed circuit board in place and twist the screws (do not pull!).
2. Connect the flexible plume, making sure it's tightly in the connector. The locker should click.
3. Check the sensor before the lid is closed – connect the battery and test the pressings.
4. Close the back cover, starting with the battery compartment, and the latches should be in place without effort.

After assembly, perform the test:

• 🔄 Reset the remote: pinch the Menu + OK 10 seconds.
• 📱 Connect to the TV: in the TV menu, select Settings → remote → Add the device.
• 🎮 Check all buttons, including the touchpad and volume wheel.

⚠️ Attention: If the remote is unstable after assembly (for example, double pressing), the cause may be a loose fit of the touch panel. Disassemble the remote again and check if debris has fallen between the plume and the board.

💡

The key to assembly is not to confuse the polarity of the CR2032 battery, plus it must be addressed to the circuit board (usually marked with a + symbol on the remote body).

Frequent Mistakes and How to Avoid Them

Even experienced users make mistakes when disassembling the Xiaomi Mi TV 4S remote. Here are the most common:

• 🔨 Use a knife instead of a mediator → scratches on the body, broken latches.
• 🔥 Dry-dryer plume overheating → plastic melting, lane detachment.
• 💦 Cleaning of payment with water or household detergents → contact-corrosion.
• 🔋 Installation of a dead battery → reoxidation.

If you are in doubt about your abilities, consider alternatives:

• 🛒 Purchase of the original remote (article) MDZ-22-AB, price ~1500–2000 ₽).
• 📱 Using the Mi Remote app on your smartphone as a temporary replacement.
• 🔧 Contact the Xiaomi service center (remote guarantee – 6 months).

FAQ: Answers to Frequent Questions