Modern. LED-TVs, including popular models from Xiaomi, Mi TV redmi TV, They have a thin body and a bright image, but they have a vulnerable element, which is the backlight system, and if the screen stops glowing, the image disappears completely or dark spots appear, one of the LED lenses probably burns out. Unlike older plasma panels, there is no single large lamp, but an array of several dozen individual diodes connected in series circuits is used.
Replacing these components requires care, because the design of the TV involves a dense assembly. You don't have to look for a single lamp, because in reality you're going to change entire LED tapes or blocks. It's a time-consuming process, but it's feasible at home with a basic tool and an understanding of how electronics work. The key is not to damage the fragile matrix when disassembling.
Before you start physical intervention, you need to accurately diagnose the problem, and users often confuse the failure of the backlight with the failure of the matrix or main board. If the indicator is lit when you turn on the TV, there is a sound, but there is no image (or it is barely visible when illuminated with a flashlight), then the problem lies precisely in the lighting of the light. LED-In this situation, installing new LEDs is the only solution to restore the device to work.
Diagnostics of illumination failure
The first step will be to test the failure hypothesis. LED-Turn on the TV and listen, if you hear the sound of a menu or channels, but the screen is black, that's a good sign. Take a flashlight and hold it close to the screen, beaming it all over the surface. If you distinguish a dim image, logo or settings menu at the spot of light hit, then the liquid crystal matrix is intact, and the problem is the lack of glow.
⚠️ Warning: Do not attempt to repair a power supply or a powered lighting driver unless you have experience with high-voltage circuits. Capacitors can retain charge even after disconnecting from the mains.
Next, you should visually examine the state of the diodes, if the TV model allows you to do this without completely disassembling, or analyze the behavior of the indicator. TV 4 or Mi TV 4A You often see the logo blinking when you turn it on, and then the screen goes out: LED-driver detects circuit break (burnt diode) and stops current to prevent fire or further destruction.
It's also worth checking the settings in the software menu, although this rarely helps with physical damage. Go to Settings → Image → Energy Saving and try to turn off all the savings modes. If the brightness hasn't changed, then the software methods are powerless. To accurately diagnose the internal circuits with a multimeter, you will need a partial disassembly, which leads us to the next step.
Tools and workplace preparation required
You can't get the new LEDs installed properly without the right tools. You'll need a set of screwdrivers, including cross and flat sizes. You'll need special attention to having suction cups or plastic cards to open the case so you don't scratch Xiaomi's glossy surfaces. Electronics are critically important multimeters to check the voltage and integrity of the circuits.
In addition to the main tool, prepare auxiliary materials. Tweezers with thin curved ends will help to gently disconnect the plumes, and isopropyl alcohol and lilac-free wipes will be needed to clean the contacts. If you plan to solder diodes manually (although it is recommended to change the tapes entirely), you will need a soldering station with a thermostat and flux.
☑️ Repair tools
Organize the workspace so that it is spacious and well-lit. You need a large flat surface, covered with soft fabric, where you will put the removed matrix. Any speck of dust caught between the layers of the screen will become a noticeable defect after assembly, so the lack of drafts and cleanliness in the room is not just a recommendation, but a necessity.
The order of disassembly of the Xiaomi TV
The disassembly process begins with the dismantling of the stand and disconnecting all external cables. Put the TV screen down on the prepared soft surface. Carefully unscrew all the screws that attach the back cover. In Mi TV models, the screws can be hidden under decorative plugs in the places where the legs are attached or around the perimeter of the frame.
When you remove the back cover, you get access to the internal modules, and it's important to remember the location of the plumes, disconnect the cables that go to the main board and the power supply, and they usually have latches that you need to bend before you take them out. Don't pull the wires, just take the plastic connectors.
⚠️ Attention: The TV matrix is extremely fragile. Any finger pressure into the center of the screen or bend can lead to vertical stripes or complete failure of the matrix, the repair of which is not economically feasible.
The next step is to remove the metal frame that holds the matrix, twist the screws around the perimeter, remove the matrix vertically up, best done by two or using special suction cups, put the matrix in a safe place with the face up, putting the supports under the edges, and now you have access to the diffusers and the LED tapes themselves.
Difficulties with matrix plumes
Replacement of LED tapes and installation
Under the diffusing films, you'll see rows of LEDs mounted on aluminum slats. Xiaomi TVs most commonly use 6 or 9 LED lines connected in series. If one diode burns, the circuit breaks, and the entire segment or screen stops burning. Changing individual diodes only makes sense with soldering equipment and skills; it's safer to replace the entire line or kit.
Carefully disconnect the power wires from the old tapes. Remove the slats, they can be glued to double-sided tape. Clean the aluminum base from glue residues and thermal pastes. Install new LED tapes, making sure they fit tightly to the metal for efficient heat removal. Use original components or quality analogues with identical voltage and size (usually 3030 or 3535).
| Parameter | Old ribbon. | New ribbon | Status |
|---|---|---|---|
| Number of diodes | 6 pcs. | 6 pcs. | Coincides. |
| Voltas | 3.0 - 3.2 B | 3.0 - 3.2 B | Coincides. |
| Power | 1 Watt | 1 W/3 W/ | Check it out. |
| Sock type | No cap (SMD) | No cap (SMD) | Coincides. |
| Color temperature | Cold white | Cold white | Same thing. |
| The length of the bar | By screen size. | By screen size. | Critically. |
After installing the tapes, take your time to assemble the TV fully. Connect the power to the board and check for the glow of the new diodes. If everything works correctly, assemble the structure in reverse order. Make sure all the plumes are snapped to the end and the screws are twisted without skewing.
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When installing new LED tapes, be sure to degrease the surface of the aluminum profile. Poor contact with the metal will overheat and quickly fail even new diodes.
Brightness setting and quality check
After successful assembly and first switching on, you might be surprised: the image will be too bright, with an unnatural hue. This is due to the fact that the new LEDs have a different light output, and the backlight driver delivers a standard current. To fix this and extend the life of new components, you need to reduce the current through the service engineer menu or with external regulators, if they are available in your model.
On Xiaomi Android TVs, you can try changing the image settings in the user menu. Go to Settings → Image → Image Mode and select Film or Standard, where the default brightness is lower than in Bright Mode. Also turn off dynamic contrast and noise cancellation, which can distort the picture.
For a deeper setup, if the model allows, you can log in to the service menu. Keyboard combinations vary, but often it's an "Up" button on the remote's joystick when you turn on the TV. Find Backlight or Current and reduce the value by 15-20%, which will reduce the load on the diodes and prevent them from overheating.
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A 20% decrease in the brightness of the backlight after replacement is almost imperceptible to the eye, but increases the life of new LEDs by 2-3 times.
Possible problems after replacement
Even with a careful assembly, there may be nuances, and if the TV turns on but goes out after a few seconds, maybe the problem isn't with the diodes, but with the diodes itself. LED-It could have been out of order because of a power surge that killed the old LEDs in the first place, and then it wouldn't help if you had to replace the tapes, repair or replace the power supply.
Another common problem is the appearance of spots on the screen ("lens"). This happens if there is dust between the diffuser and the LED, or if the plastic lens of the diode is shifted, you have to take the TV apart again and wipe the surfaces. Also check if all the bars are even: if one is skewed, it can create a shadow or uneven illumination.
⚠️ Warning: If you see vertical stripes on the screen after you've been replaced, it's likely that the matrix plume was damaged during disassembly. It's almost impossible to restore it at home.
Sometimes there is a color rendering problem: If new diodes have a different color temperature (for example, a cooler hue), the picture can go blue, in which case only software calibration of the image through the service menu or the installation of color filters will help, although the latter is a last resort.