Without such a backlight, no LCD TV can work normally, regardless of its brand. We will tell you how you can repair LED TV backlighting at home using an example of a device from Lg, and what you need for this.
How can you tell if the backlight is broken? Suppose that the LCD TV's malfunction is as follows: it turns on from the remote control, but the screen does not light up (if your TV does not turn on even from the remote control, read about). When the display is directed flashlight (i.e. forced illumination is implemented), then the image is developed. Verdict - the ice driver or similar backlighting does not work, maybe due to the fact that special rulers with soldered LEDs burned out. It is necessary to disassemble the TV and visually inspect the parts in search of a malfunction.
Attention! You can open the case of an LCD TV only if you have the skills to work with complex devices and a little experience, otherwise it is better not to risk it.
Remove the back cover any LG TV is a simple matter, you just need to do everything carefully and without haste: disconnect the legs of the stand and unscrew the mount around the entire perimeter of the product. If the cover cannot be removed, then there is a locking bolt, you should not make any efforts, you need to find it and unscrew it.
After removing the back cover, we check the output voltage.
If it is normal - check backlight ice voltage the screen itself. Its value is only 100V, which indicates the presence of a malfunction of the LCD TV backlight.
In such TVs, a special LED set with lenses is used, which is installed over the entire screen area to provide clear illumination. To get to them and repair the LG TV backlight, you must first remove the matrix.
Disassembly of the product
The TV has three main boards - main, T-con and power supply, all of which are clearly visible in the photo.
Removing and disassembling the matrix do it yourself - the work is very painstaking, one careless movement, and you can buy a new TV set, so without experience it is better not to undertake repairs. Experts highlight the following main points when disassembling the matrix:
- it is necessary to prepare a place of work and two tables on which to lay matrices and scattering films;
- before starting this work, you should thoroughly wash your hands so as not to accidentally leave traces of dirty fingers on the filters and the matrix itself - this can harm the image quality later;
- special attention should be paid to decoders - one inaccurate movement can lead to a loop break.
Subsequent dismantling is carried out in several stages.
Troubleshooting
Now the direct repair of the LED TV backlight begins: to do this, you need to carefully snap off all the latches along the contour, remove the plastic frame and remove the diffusing films to open the LEDs.
Have different models LG TVs will have their own set of ice backlighting: for LG 32LN541U - these are three rows of 7 LEDs, and for LG 32LB582V - three rows of 6 pieces.
In all TVs that use such a backlight, LEDs are connected in series, so if one of them burns out, the whole system stops working. If the LED driver is faulty, then the voltage is not supplied to the entire system, and when one of the LEDs burns out, the voltage goes on, but all the efforts of the device to light up 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, for each there was 7.8 V. When we take into account the voltage drop on each bar and the total load, the conclusion will be as follows: this model is used 6V LEDs.
Finding a burned-out LED is not easy: if there is no burning at the attachment point, then each element must be checked separately.
Replacing LEDs
Replacing the Lg TV backlight can be difficult. Let's say that the test 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 not be easy to find them on the radio market. Experts assure that you can buy already soldered, but serviceable ones, after a long search, these are exactly the ones that were purchased.
Users should be aware that all planks are glued with double sided tape, so you need to warm them up with a special soldering hairdryer so that the adhesive tape comes off. To do this, the bar is fixed in the holder and heated from below with a hairdryer, the tin is melted, and the faulty part is removed. Solder in exactly the same way so as not to damage the LED.
Important! All lenses are fixed at the factory with a compound, therefore, when removing them, you must act very carefully, while each must then be reinstalled in order not to disturb the initial focusing.
Another nuance: you may come across LEDs with a minus pad that is slightly larger than the plus one, so you need to cut the contact point to solder the diode. This is what a soldered LED looks like:
The fact that the paint is slightly damaged is not a problem. We solder the remaining LEDs in the same way, and glue the lenses on superglue... And this is a repaired view of the assembled and ready-to-use backlight panel:
As we can see in practice, there are many specific nuances in the repair of 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 system of LG TVs has been carried out completely, before making the final assembly, we connect the voltage to the strips and check the glow of all LEDs... If everything is fine, then we assemble the TV, performing all operations sequentially and with care, as in the case of dismantling.
After the end, it is better not to set the backlight brightness to maximum, but to limit it to 75% - in this mode, the LEDs work in normal mode and, according to experts, will last much longer.
We install the TV in its original place, turn it on and enjoy the quality: if there are no extraneous spots of light or dark color anywhere on the screen, then the repair was carried out correctly, following all the recommendations. And to get the most out of your TV, you can learn how to
The most reliable LG TVs of 2018
LG 22LH450V TV
LG 49UJ651V TV
LG OLED55C8 TV
LG 55LJ622V TV
LG 55UK6100 TV
TVs with dynamic backlighting around the display frame is one of the proprietary chips of Philips. And unlike many others, it works. Everything comes at a price, though, and TVs with Ambilight and immersive presence are more expensive than many others.
Russian developers have proposed a method that will equip monitors of any manufacturer with dynamic backlighting. To do this, you don't even have to carry the device to service center: it only takes a little time and perseverance.
In general, such a backlight can be purchased as radio components and configured on your own. But, as practice shows, this is almost comparable to the ready-made options from PaintPack.
There are two main models available: a monitor version (30 LEDs) and a TV version (60 LEDs). There is also a very simple one - for 10 LEDs, but it is suitable only for the smallest monitors.
The TV version is equipped with an external power supply. Also, a larger number of LEDs speaks in its favor, which gives a larger illumination area (it will shine wider and higher, in other words). If such options are not suitable for any reason, you can contact the developers: for a small surcharge, they will offer a modified version.
mindrunway.ruPaintPack, in fact, is a small case, to which removable LED strips are connected from both sides. The box with the filling carries indicators and a power connector, as well as a microUSB for connecting to a PC. There is also a master connector (proprietary) for daisy chaining two devices.
The device body is located on the back of the TV or monitor. Then LED strips are laid in accordance with the instructions, power is connected and witchcraft begins. When connecting PaintPack to a computer via a USB connector, you need to install drivers and configure the device in the bundled program.
mysku.ru The setting is done using the AmbiBox package. It is necessary to go to the "Intelligent backlight" menu, select a screen capture method and one of the operating modes offered in the program:
- Static background - any color can be set, LED glow is regulated.
- Color music - the backlight will flash in time with the sound of music. The backlight color is set to green-yellow.
- Dynamic background - smooth flow of one color into another.
- Screen capture is the main mode of operation.
In this mode, you can capture color from the movies and games you are watching. The backlight color will change in accordance with the image on the screen, dividing into top, bottom and side zones (each separately).
PaintPack is slightly slower than official counterpart from Philips. But taking into account the difference in cost and the possibility of upgrading any device, the choice is obvious.
Ambilight technology
The proprietary backlight technology of the aforementioned company is special lamps built into the TV, which allow a soft glow to be projected onto the wall behind the TV in a certain way, which, as it were, continues the picture from the screen to increase immersion in the atmosphere of what is happening on the screen.
The technology itself was born in the last century due to the fact that, on the one hand, the brightness of the then TV receivers was insufficient, and the viewers turned off the light when watching them, on the other hand, watching TV in the dark put a sharp strain on the eyes, which led to rapid fatigue and general discomfort. The solution was obvious - the presence of a scattered light source nearby (the so-called TV lamps). Today, according to the research department of Philips, this problem designed to solve the technology "Ambilight".
At the moment, there are already 5 generations (and a lot of modifications) of this technology, of which the last three are the most common:
- Three-channel backlight technology « Ambilight Surround»With additional lamps on top of the housing to expand the field of effects upward and independent binding of the left, right and upper block of background lamps to the corresponding area of \u200b\u200bthe screen.
- Full backlight technology " Ambilight Full Surround”, Where the screen is already surrounded by lamps on all sides. Accordingly, the processor responsible for controlling the lamps builds background image on the analysis of at least four areas of the image on the screen. For better transmission light, the TV case is equipped with a rear panel-screen.
- Technology " Ambilight Spectra", Which allows you to create a" three-dimensional "image thanks to more than 120 new generation LEDs and improved image processing algorithms.
All technologies in one way or another create diffused light behind the TV, which complements the color and light intensity of the image displayed on the screen.
What can you say at the end of the review? The device is undoubtedly interesting and worth trying out, especially since the manufacturer provides a free test drive for 30 days, i.e. if you don't like the device, you can return it and get your money back. Your costs in this case will be equal to the postage to the manufacturer. The main disadvantage is that the device works only in conjunction with software, which means that a computer is needed to get the effect. dynamic backlight.
Outcome
Well, the bottom line is:
pros
- work with any type of monitors and TVs connected to a computer;
- low system requirements to the PC hardware;
- fully implemented functionality that does not differ from that declared by the manufacturer;
- good software support, including by third-party software vendors;
- the ability to customize the product and create non-standard solutions;
- low price;
- ample opportunities for payment and delivery of goods;
- easy to install and configure;
- russian language service technical support;
- detailed text and video instructions on the manufacturer's website;
- free test drive.
Minuses
- you need a computer to get the effect of dynamic lighting;
- lack of software in the delivery, the need to download it from the Internet;
- lack of instructions (even electronic) in the kit, the need to read it on the manufacturer's website;
- lack of a number of fastening elements (double-sided tape) for LEDs;
- the need for a certain location of the screen (15-30 cm from the wall) to obtain the most correct effect;
- absence warranty card and the manufacturer's details both on the packaging and on the product itself.
Backlit.
The option proposed below differs from those already discussed in that the backlight turns on automatically, does not require changes to the design of the TV and can work as an emergency lighting.
Of the shortcomings, it should be noted that the backlight is static, it takes time to install and configure for specific equipment.
Formulation of the problem
So, we need a backlight that turns on when the room is dark enough and the TV is turned on, it burns in half-light when the TV is not working, but the room is very dark and someone is walking on it. In all other cases, the backlight must be off. Limitations: equipment under warranty - you cannot climb inside.Decision
To determine the operating mode of the TV, we will use this thing:TAK12-02 High-frequency Pulse Current Transformer
The device allows, by inserting one of the power wires into the hole, to remove the induced current from the contacts, and by its value to draw a conclusion about the operating mode of the TV. Suppose that for a TV in sleep mode, the current consumption will be significantly lower than in active mode. We will measure the illumination with a photoresistor, aka LDR, record movement around the room using PIR, and an arduinka will control everything. The scheme turned out like this:
Backlight connection diagram
Implementation
The backlight is led stripglued to a plastic corner. While he just lies behind the TV, then I'll screw it to the wall.
Backlight
Ready device
After the first test launches, I was in for an epic fail a little disappointment - it turned out that the plasma TV is very hard to fall asleep - it may take up to half an hour for it (see the graph below). In addition, he sleeps very anxiously, waking up every 2-3 hours for 15-20 minutes.
Panasonic TX-P50G30 goes to sleep. Y-axis - current in parrots, X-axis - time in seconds x2.
All this, plus the cat on which the PIR was triggered, led to the fact that "light and music" worked in the living room all night long. But given that the TV is used only in tandem with a tuner, and it has fewer sleep problems, the problem was solved, although not as beautifully as planned. It was possible to reduce the influence of kote on the system by gluing the lower part of the PIR.
Refined backlight connection diagram
Current consumption by the tuner. Y-axis - current in parrots, X-axis - time in minutes.
As you can see in the picture above, the tuner, unlike the TV, immediately goes into sleep mode, which is noticeable by the decrease in current. The tuner also has moments of extreme power consumption, marked on the “burst” graph, and they can occur in both sleep and active modes. To increase the reliability of determining the operating mode, the measurement flow was divided into series of 3 minutes, for each series the mean value (SD) and standard deviation (RMSD) were calculated. We took into account only the values \u200b\u200bof the series with a small standard deviation and SZ not falling into the “burst” zone. All this made it possible, with a delay, but quite accurately to determine the mode of operation of the tuner.
Expenses:
I am not strong in circuitry, the details were taken according to the principle "what are", I will be grateful for comments and additions: 
Electric circuit, not basic.
A sketch for arduino can be found.
conclusions
- The idea of \u200b\u200bdetermining the mode of operation of the device by power consumption, in practice, turned out to be not so good. A cumbersome algorithm, a significant lag in work, the need fine tuning, make the commercial implementation of the Idea impossible, but as a hobby of the project it has the right to exist.
- Energy statistics collected during work gives you a reason to think about what you are doing appliances with sleep mode, especially if it is connected to the internet.
The device is assembled.
Backlight in operation.
Update.
- Vigilant noticed an error in electrical diagram, thanks, corrected.
- I took into account a fair comment and slightly changed the name of the topic.
- I added a picture of a TV with a working backlight, just as an illustration of the fact that throwing an LED strip behind the TV can increase the viewing comfort. I will not make a video - in my opinion, it is not informative for static lighting.
- Moved to DIY, thanks for the karma.
Since the idea of \u200b\u200bcontrolling the current consumption is not an ideal way to determine the operating mode of a TV, at the end of the topic I present, in collaboration with, and other respected commentators, the following table.
Alternatives
| Way | Advantages | disadvantages |
|---|---|---|
| Solder to status LED | reliable, reliable | unsportsmanlike, it is necessary to open the TV |
| Set FP to control the status LED | reliable, reliable | the front panel of the TV changes - not aesthetically pleasing |
| Catch leads from the sweep plasma TV using an antenna located behind the screen | cool, no need to pull wires to the TV | research necessary, suitable only for plasma |
| Monitor the temperature of the TV | simplicity, reliability | delay in detection, additional wires from the sensor, possibly suitable only for plasma |
| Analyze the presence of a signal on one of the wires included in the SCART connector | simplicity, reliability | research is needed, one of the connectors will be busy, additional wires |
| Put the FP in front of the TV and determine the glow of the screen | if you put a matrix from FP, you can organize a full-fledged ambient light | additional wires, complexity of placement, the need for an additional optical system |
| Catch IR signal to turn on / off the TV | simplicity, minimum of wires | no feedback - possible malfunctions |
| Monitor the power supply on USB portat | simplicity, reliability | not suitable for all TVs, occupies a USB port, additional wires |
| Analyze the current consumed by the TV | minimum of wires | complex algorithm, delay in detection, not applicable to all TVs |
Update 2.
Practice has shown that the ACS712 Hall effect microcircuit measures current much more accurately than the TAK12-02 transformer. Therefore, its use is preferable. 
Signal from ACS712 when measuring current consumption by computer. 0 corresponds to 2.5V
