Even the best quality equipment experiences various glitches and malfunctions. Therefore, every user should be prepared for the fact that they will have to repair the equipment with their own hands, because paying for the services of service centers can go broke.
Today we will talk about the most popular failure - a malfunction of the LED backlight on LG TVs. It is with this problem that ordinary users most often turn to service centers. Few people know that you can normalize the operation of the device on your own. No special skills are required, the main thing is to follow the instructions.
Before you start repairing the LG TV backlight, you should first understand how this component works, what are its functions and why is it even needed?
Diagnosis of LED backlight malfunction
We will start repairing the LED backlight of the LG TV matrix by preparing the workplace, since when disassembling the TV we will need a separate table on which we will arrange such fragile parts as the matrix and light filters. I always repair such TVs with trepidation, since one wrong move can send the matrix to scrap.
Having laid the TV down, I unscrewed all the bolts around the perimeter of the cover.
TV after disassembly
Having removed the cover, I decided to measure the voltage on the LED driver at the moment it was turned on.
Connector for LEDs
At the moment of switching on, the voltage rose to 130 volts, after which it slowly dropped to zero. This behavior of the driver is normal, since if there is no load, it goes into protection and turns off the power.
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Preparing for work
To repair an LED TV you will need:
- a professional soldering station that blows a thin stream of very hot air, later referred to as a hair dryer;
- flux;
- some tin for tinning the contact pads;
- depending on the chosen replacement strategy, a small amount of thin copper wire;
- scissors;
- tweezers;
- Super glue.
You will also need the main tool, a device for checking the LED lines of LED TVs. It could be a multimeter. It is convenient to operate as a tester with the ability to set the operating voltage. A laboratory transformer with thin contact probes performs well. How exactly to use these devices will be clear from the following sections.
In order not to damage the matrix elements and other complex components of the TV, it is advisable for the technician to prepare a lot of free space for himself. At least two screen sizes. This area will house a separate matrix and LED backlight unit.
Important! It is undesirable to leave fingerprints and other dirt on the lenses, reflectors, display and protective film, so you need to thoroughly wash your hands and clean the TV case. It would be a good idea to stock up on lint-free wipes, wear tightly fastened, clean overalls, work in a dust-free room, and use antistatic wristbands.
Identifying faulty LEDs
After disassembling, I saw that the previous craftsmen had cut out the faulty LEDs from the strip, after which LEDs from other strips were installed in their place. They did it well, there are no complaints about the quality of the work done.
LEDs that were replaced in a previous repair
Closer view
To find faulty LEDs, I used a laboratory power supply. I installed two thin sewing needles on the tips of the crocodiles.
Preparing for the test
To determine the rating of the LEDs, I first set the voltage to about 3 volts and checked whether the LED was lit. Next, I raised the voltage to 5 volts and a penny, and repeated the test. The LED lit up, which meant that 6 volt LEDs were being used.
Checking LEDs
Thus, I checked all the LEDs and found only one faulty one. At this stage, it is necessary to agree with the owner on the type of repair.
When repairing backlights, it is better to change all the LEDs, since in any case the old LEDs can fail at any time, which will lead to repeated repairs. If you do not want to change the LEDs, you can order complete strips.
The owner expressed a desire to install new trims. Since they are not available, I ordered them from China in his name. While waiting, it was decided to restore the TV by replacing just one LED. After a repeated breakdown, the owner will arrive with replacement slats, and this will reduce the repair time to a minimum. True, it is unknown when this breakdown will occur, perhaps the TV will work for a very long time
