Independently repairing LED backlight in LG TV

Without such a backlight, no LCD TV can work normally, regardless of its brand. We will describe how you can make repairs Led TV backlight at home on the example of a device from Lg, and that for this you will need.

TV diagnostics

How to determine that it is broken backlight? Suppose that the malfunction of the LCD TV is as follows: it is turned on from the remote control, but the screen does not glow (if your TV does not turn on even from the remote control - read about possible methods of reanimation of the remote control). When the display is directed light from the flashlight (i.e. forced backlighting is performed), then the image appears. Verdict - the driver or similar backlight does not work, maybe due to the fact that special lines with soldered LEDs have burned out.It is necessary to disassemble the TV and visually inspect the details in troubleshooting.

Attention! Opening the case of the LCD TV is possible only if you have the skills to work with complex devices and little experience, otherwise it is better not to risk it.

Remove the back cover for any LG TV brand, it’s simple, just do everything neatly and without haste: disconnect the legs of the stand and unscrew the mount around the entire perimeter of the product. If the cover is not removed - then there is a locking bolt, you should not make an effort, you need to find it and unscrew it.

After removing the back cover, check the output voltage.

If it is normal - check voltage ice backlight the screen itself. Its size is only 100V, which indicates the presence of a malfunction of the backlight of the LCD TV.

In such TVs as ice type lights A special LED kit with lenses is used, which is installed over the entire screen area to provide clear illumination. To get to them, and to repair the backlight of the LG TV, you must first remove the matrix.

Disassembly of the product

The TV has three main boards - main, T-con and power supply, they are all clearly visible in the photo.

Removal and disassembly of the matrix do it yourself - the work is very painstaking, one careless movement, and you can buy a new telly, so without experience it’s better not to undertake repair. Experts identify the following highlights when disassembling the matrix:

• it is necessary to prepare a place of work and two tables on which to lay the matrix and scattering films;
• before starting this work, wash your hands thoroughly, so that you do not accidentally leave traces of dirty fingers on the filters and the matrix itself - this can harm the image quality afterwards;
• special attention should be paid to the decoders - one inaccurate movement can lead to a break in the loop.

Subsequent dismantling is carried out in several stages.

1. T-con board easily removed after disconnecting the loops and unscrewing the bolt located between them.
   
2. It is necessary to remove the metal protection from the decoders - to do this, unscrew the mounting bolts on the sides, after that they are held only on rubber mounts.
   
3. It's time to remove front frame tv - unscrew the mounting bolts around the entire contour, put the product on the back cover and remove the frame.
   

4. We remove the frame, turn over the screen, but at the same time carefully hold the matrix, because it is not fixed by anything. The product lies on the matrix, decoders located on top and can be removed from the rubber mounts, but with extreme caution.
5. The matrix remained lying on the table so that it would not interfere with further work - shift it to a previously prepared place.

Troubleshooting

Now begins the direct repair of the TV's backlight: to do this, you need to gently snap off all the latches along the contour, remove the plastic frame and remove the scattering films to open the LEDs.

Different models of LG TVs will have their own set of ice backlighting: for LG 32LN541U - these are three rows of 7 LEDs each, and for LG 32LB582V - three of 6 pieces each.

In all TVs that use such a backlight, the LEDs are connected in series, so when one of them burns out, the whole system stops working. If the LED driver is faulty, there is no voltage applied to the entire system, and when one of the LEDs has blown, the voltage goes, but all the efforts of the device to light the system are in vain: at least give 200 volts, the circuit is open.

As you can see from the photo, the backlight consists of 18 LEDs, when measuring the voltage without load was 140 V, that is, each accounted for 7.8 V. When we take into account the voltage drop on each bar and the total load, the output will be as follows: in this model are used 6 V LEDs

Finding a burned out LED is not easy: if there is no burning at the point of attachment, then each element must be checked separately.

LED replacement

Replacing the backlight of the TV Lg can cause some difficulties. For example, the test results revealed several faulty LEDs. It is rather difficult to buy a replacement bar - these parts are not supplied to service centers, you can order them on the manufacturer's website, but this is long and very expensive. So there is only one way - replace individual diodes, although it will be difficult to find them on the radio market. Experts claim that you can buy already soldered, but serviceable, after a long search, it was these that were purchased.

Users should be aware that all strips are glued with double sided tapetherefore it is necessary to warm them up with a special soldering dryer so that the scotch tape goes away. To do this, the bar is fixed in the holder and heated from below with a hairdryer, the tin is melted, and the defective part is removed. It should be soldered in exactly the same way so as not to damage the LED.

Important! All lenses at the factory are fixed with a compound, therefore, when removing them, you must act very carefully, with each one then having to be installed in its original place so as not to disturb the initial focusing.

Another caveat: you can get LEDs, in which the negative ground is slightly larger than the positive one, so you need to cut the contact point to solder the diode. This is what a soldered LED looks like:

The fact that a little paint is damaged is not a problem. Similarly, solder the remaining LEDs, and Glue the lenses on superglue. And this is the renovated view of the backlight panel assembled and ready for further operation:

As we see in practice, there are many specific nuances in repairing the led backlight of the LG TV matrix, and without knowing them, it is impossible to achieve a positive result.

Final work

When the repair of the Led TV system of the LG brand was carried out completely, before making the final assembly, we connect the voltage to the slats and check the glow of all LEDs. If everything is normal, then we assemble the TV, performing all operations consistently and with care, as during dismantling.

After the end of the backlight brightness is better not to bring to maximum, but to limit to 75% - in this mode, the LEDs work in normal mode and, according to experts, will last much longer.

We install the TV in the same place, turn it on in the network and enjoy the quality: if there are no extraneous spots of light or dark color schemes anywhere on the screen, it means that the repair was done correctly, in compliance with all the recommendations. And you can get the most out of your TV by learning how to properly tune digital channels on an LG TV.

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