How to check the LED backlight of the TV

TV production over the past decade has reached a new level. The quality of the resulting image, sound and various screen configurations allow you to achieve the effect of complete immersion in the atmosphere of the events taking place on the screen.

However, despite the fact that there are TV receivers in every home, few understand how they are arranged and function. In modern models, one of the key functions is played by LED backlight, without which video will not be displayed and playback will stop. In our article, we will consider the possible causes of malfunctions and talk about repair options.

You should understand the principle of work in order to learn how to identify possible malfunctions. To do this, refer to the operating instructions or read about the TV device. For convenience, we offer the following troubleshooting plan if the TV fails:

  1. First, it is necessary to exclude other causes of failure. Check the network connection, the operation of the console and the integrity of the case.
  2. If there is no image when turning on the TV using the remote control, try lighting the screen with a flashlight from the outside.
  3. When a picture appears under the action of a flashlight, there is no doubt that the reason lies precisely in the backlight, without which the image is missing.

Most likely, the blown LEDs were the source of the malfunction. Usually they are fastened in rows on special strips. For an accurate determination, remove the cover from the screen and disassemble its back panel.

IMPORTANT! Perform all actions carefully so as not to damage the parts. If you do not have experience, then it is better not to take risks.

If you decide to disassemble the structure yourself, then it is worthwhile to carry out all the actions according to plan and not to rush. Dismantling is not particularly difficult, but you should carefully consider this process:

  1. In turn, unscrew the retaining fastenings of the back cover from all sides.
  2. Then slowly remove the cover. If this fails, then you have not unscrewed all the bolts. Carefully inspect the part, remove the fasteners to the end.
  3. After you get access to the boards and microcircuits, you need to check the output voltage. At values ​​of 100 V, we can speak of a malfunction of the illuminating part.
  4. In order to get directly to the LEDs, you must first remove the matrix, which consists of three main boards.

The subsequent disassembly of the boards and microcircuits should be entrusted to the master, since there are a lot of small parts in this zone, damage to which can lead to serious problems and break the screen. The main stages of work will consist of the gradual removal of the T-con board, detachment of the metal protection and decoders (especially painstaking manipulation), detachment of the front panel of the screen.

IMPORTANT! Prepare the workplace and table in advance for laying all the parts. You need to work only with clean hands or gloves so as not to contaminate the matrices and decoders.

When gaining access, you can begin to search for the source of the problem. To do this, remove the plastic circuit and release the LED backlight. Depending on the model and year of manufacture, each TV will have its own peculiarity in the location of the diodes. Their common drawback is serial connection. That is, when even one element burns out, the entire chain ceases to work. Therefore, the image disappears on the screen.

The principle of verification is based on calculating the voltage and identifying a faulty element:

  • when the driver breaks down, the voltage does not reach the circuit;
  • if the bulb burns out, then the voltage goes on, but with an open circuit there is no effect;
  • it will be easiest to detect a breakdown during burnout and a characteristic black spot from the flash;
  • if there is no spot and it is not possible to visually establish the source, the check will need to be carried out sequentially for each element of the system.

If a burnt out LED is detected, it must be replaced with a new element in order to restore the normal operation of the circuit. It's hard enough to find replacement parts. Separate strips with bulbs are not delivered to stores, and only individual parts can be purchased on the market. Most likely you will have to work with already used and repaired items.

  1. Remove damaged parts first. Usually they are mounted on double-sided tape. It can be melted with hot air from a hair dryer.
  2. Separate the part and remove any burnt out LEDs.
  3. Replace using purchased items. You may have to cut one of the edges of the part, since non-native elements may be slightly larger than the original socket.
  4. Solder it also with a hairdryer.
  5. Install the lenses over the native strip.
  6. Check the operation of the entire circuit.
  7. In the case of normal operation, carefully assemble the entire structure in the reverse order.

For replacement, it would be better to contact the workshop or carry out repairs under warranty. Independent work can lead to even greater problems.

Watch the video: Testing TV Backlight LEDs (March 2024).

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