We make bright and economical LED backlighting from a broken LED matrix (how to make the matrix backlight work without a laptop). Repair of LED backlight of TV matrix UE32F5000AK

LED backlighting is another characteristic of TVs and monitors, which has recently complicated the buyer’s choice, requiring him to think twice and make a responsible decision... The fact is that there are more and more LCD TVs, and their types are increasing time multiply.

Indeed, when purchasing a TV, you want not to make a mistake, not to buy something that represents yesterday or the day before yesterday, which you will soon no longer be able to use...

Fortunately, there are no big difficulties in this issue; its importance is greatly exaggerated - more on this below on the page...

Eat good rule: When buying a TV, it is recommended to pay less attention to the names of the technologies used, and be more guided by your impressions of its appearance and image quality.

At the same time, of course, a more modern (and expensive) TV will in most cases be of better quality.

Best results In terms of image quality today, perhaps, the backlight type is Direct (Full) LED. Moreover, it is being improved all the time - now this technology can be used very large number LEDs, which, naturally, has a very positive effect.

Edge LED or its derivatives also show more and more best characteristics, also allowing you to make TVs very thin.

In both cases in best models TVs also use the “Local Dimming” method - Local Dimming. In LG TVs, the backlight using it is called LED plus.

The LCD elements that make up LCD TV panels will not produce images on their own unless they are backlit. Therefore, one or another type of illumination in modern TVs definitely present. It should be borne in mind that technologies are constantly being improved, and the type of illumination with the same or similar name next year may be very different in execution from last year. For example, Full screens LEDs now come in nearly as thin as Edge LEDs.

Among the types of TV backlights used or used by SONY are the following:

CCFL (Cold Cathode Fluorescent Lamp).

WCG-CCFL (Wide Range Backlight) color range cold cathode fluorescent lamps).

RGB LED, or dynamic rgb led (Provides color illumination of individual fragments of the monitor or TV screen. Potentially a very promising technology, since in theory it makes it possible to illuminate the desired area of ​​the screen a certain color. In practice, its theoretical advantages compared to other types cannot always be realized. See details below on the page).

Full LED. Another name is Direct LED (backlit diodes are located behind the screen evenly over its entire area. This simplifies control and improves quality. But it negatively affects the thickness of the screen.) - Edge LED (The liquid crystal screen is illuminated by white LEDs installed at the top and bottom or on the sides . Allows the production of very thin Slim TVs).

Dynamic Edge LED (In addition, Local Dimming technology is used, which controls the amount of illumination of individual groups of LEDs depending on the displayed image).

Intelligent Dynamic LED. Another name is Full LED or Direct LED (Compared to previous technologies, many more white illuminating LEDs are used, located directly behind the TV screen evenly across its entire area and illuminating the image. By controlling the glow of individual blocks of LEDs, the system can illuminate specific areas of the image, leaving others dark. This technology simplifies operation and improves quality, but has a negative impact on screen thickness.)

Other TV manufacturers, Samsung, Sharp, LG or Toshiba use different technologies to varying degrees. Accordingly, the TV backlight options may also have a different name (you can get a lot of information about technologies on the Internet, but from the point of view of choosing an option for purchase, this information will not give much. It is more important, as we have already said, to evaluate the TV picture visually).

By the way, Full LED (Intelligent Dynamic LED) from Sony is not the same as full LED backlighting in the original sense at the beginning of technology development, when the fluorescent lamp backlight of the LCD matrix of TVs was simply replaced by thousands of individual light-emitting diodes (LEDs).

Compared to previously used technologies, LED LCD backlight(LCD) TVs have quite a few advantages, but there are also disadvantages (inherent to the technology itself):

Disadvantages of LED technology

Initially, this type of backlight does not improve the viewing angles of the LCD (LCD) display
- Thinner models with edge LED backlighting may suffer from uneven screen illumination
- LED backlighting can lead to local unwanted darkening of the image.

Of course, these shortcomings in most cases are successfully overcome in specific models TVs and monitors, since the technology itself is improving all the time. In addition, not only the backlight affects the quality of the picture on the screen.

Advantages of LED TVs

All types LED backlight more economical
- Technologies such as Edge LED allow you to create TVs with very thin screens
- LEDs do not contain mercury (although their manufacturing technology uses gallium and arsenic)

Of course, miracles do not happen. As a rule, a more expensive model will have a higher quality image and is considered the most promising at the moment time type of screen backlight. But the image will be good not only and not necessarily because of the backlight. All other TV devices, including the video processor, can be very good quality. The TV can be very well tuned (what used to be called "calibrated"). In the end, adjustments can be made correctly and appropriately for the given lighting...

From all this, in our opinion, we can conclude:

When choosing a TV, you should not pay much attention to the type of backlight. It will be better if you personally compare the image quality of several models and choose the one whose picture seems nicer.

And choosing which type of backlight is better is the task of manufacturers. While they themselves cannot come to an established opinion (which is natural, because technology is moving forward very quickly).

Take for example RGB LED backlight It is believed to provide a much richer color gamut, extremely sharp and contrasting images on the screen, but it has not become widespread over time. On the contrary, it seems that manufacturers are abandoning it. Firstly, it is much more expensive than other types. It also has technical limitations: the number of backlight elements is limited, since controlling every part of the monitor is too difficult and expensive. As a result, some of the scene illumination that should be bright may be reduced.

Addition:

Lately There is information about successful improvements to this technology by Mitsubishi. Moreover, they are developing completely new type RGB Backlit lighting using a three-color laser. Perhaps soon they will start talking about RGB lighting again in full voice.

Sergey Filinov

Every person, when choosing a TV for themselves, learns about the latest achievements of science, gets acquainted with new technologies and terms. One of modern technologies in the field of television is LED. In reality, an LED TV is an ordinary liquid crystal LCD TV. This means that the image in it is formed using a matrix consisting of pixels.

If in older devices the backlight was a fluorescent lamp, then in LED models the backlight is a matrix consisting of a set of LEDs (Light Emitting Diode).

Light Emitting Diode is translated as “light emitting diode”. The scope of their application is extensive: these are car headlights, traffic lights, lamps, spotlights, street and home lamps. In a TV, light from LEDs is directed onto the LCD screen, illuminating the image.

Of course, it would be more logical to call these models LCD TVs with LED backlighting. However, Samsung, which is a pioneer in this field, called these models "LED TV". The term became popular and began to denote a class of new televisions. The LEDs in these TV receivers do not form a picture as a real unit (pixel). Therefore, LED TVs cannot be considered full-fledged LED models.

How LED lighting works

To understand the operating principles and features of this device, you need to become familiar with the types of backlighting on a TV. Currently, several lighting systems have been developed. They differ from each other in their location and color.

Color of glow sources

Single color system (White led) more energy efficient than fluorescent lamps, but still considered budget option. LEDs do not contain mercury, like lamps, but in terms of color rendering and coverage depth, LED TVs with this backlight are practically no different from LCDs.

Multi-color system (RGB) compares favorably with the previous version. TVs with this backlight have a wide color palette. Accordingly, very good color rendition. Unfortunately, this effect comes at a higher price. To operate such models you need a modern, powerful GPU. These TVs consume more electricity and have a more bulky, comparatively, of course, body. The cost of these TVs limits demand, so leading companies are gradually abandoning RGB backlighting and are looking towards analog household appliances.

Mixed backlight option (QD VIsion) uses LEDs only blue and special films. The film is a collection of quantum dots that have red and green colors. This allows you to have a tuned spectrum of optical waves, limited in range. Due to this, the color palette expands, and the brightness and intensity improves. Unlike the RGB system, this technology is more energy efficient.

The answer to the question of which backlight option to use is ambiguous. There are still various controversial opinions and discussions on this matter. Toshiba believes that white backlighting, based on all its characteristics, is preferable to RGB.

Accommodation options

There are two options for placing the backlight:

General advantages of LED TVs

These devices are an undoubted step forward in the development of television. They enjoy deserved popularity in everyday life. There are several main advantages:

Manufacturers are constantly working to improve these panels. The new technology is called OLED TV. In these TVs, the backlight is organized using organic light-emitting diodes. They are even more characteristic slim body and improved color rendering.

Speaking about LED technologies, we should not forget that in the manufacture of LED TVs they do not use, as before, harmful substances - mercury and aerosols.

Some LED-TV models use “local dimming” technology. It is designed for local dimming. The basic idea is to control groups of LEDs. Each group contains several elements. True, with such an approach separate areas bright spots sometimes appear on the screen in areas where the backlight is turned on full power. And where the backlight is not used, dark spots may appear.

Screen resolution. Determined by the number of pixels that form the image in width and height. The larger this parameter, the more clear image and more different details can be seen on the screen.

LED-TVs mainly have Full HD (1980×1920 pixels) and H.D. Ready (1366×768 pixels) resolution. These are the most popular video formats in present moment. Some premium models have 4K UHD resolution (3840x2160 pixels).

Almost all 4K UHD TVs support HDR. This is an extended format dynamic range, which allows you to depict a picture as close to reality as possible.

Screen coating. There are matte and glossy. At matte finish the image is softer. Viewing angle is limited. When hit sunlight no glare. If the coating is glossy, then the picture on the screen is very bright and contrasting. In bright sunlight, visibility becomes worse.

Functional connectors. Usually there are standard ones: HDMI output, Ethernet output and USB connector for watching video from a flash drive or hard drive. IN latest models there is a D-sub video port. It involves connecting a computer to a TV.

Sweep frequency. An indicator of how many frames of a film are shown per second. It is measured in Hertz and can reach values ​​up to 960 Hz. For 3D TVs, the frequency can be even higher. The recommended range of values ​​so that the image does not blur and pictures do not overlap one another is 100−200 Hz.

Additional features

DVB-T. Standard digital television. Allows, in addition to analog cable and terrestrial television, connect satellite.

Volumetric 3D image. Using this option, you can view 3D images with active or passive 3D. It is necessary to take care of special glasses.

Smart TV. Allows you to connect and use the Internet. Connection occurs via WiFi module. Connection possible via network cable. Some TVs allow you to build in an additional router. With Smart T.V. you can play videos from the Internet, play, listen to music, and search for information.

LED devices have become popular. After all, LED TV - what does it mean? This high quality, convenience and comfort of use. The advantage of an LCD TV is LED backlighting; all LED models have it. But for the design features, additional features sometimes you have to pay extra. What should you pay attention to when choosing an LED TV model?

First of all, you need to decide which diagonal is best to choose. The stores offer a huge selection different models from 19 to 58 inches. Sometimes it’s not very common to calculate in inches and you have to select the size in centimeters, that is, from 48 to 147 cm. The right choice diagonal depends on the size of the room where the TV will be installed.

There is an approximate table of the ratio of diagonal and distance to comfortable viewing.

These data are approximate and allow adjustments within half a meter.

• 14−17 inches - from 1.5 to 2 m.
• 21−25 inches - from 2 to 3 m.
• 26−32 inches - from 3 to 4 m.
• 34−37 inches - from 4 to 5 m.
• 42−55 inches - from 5 to 7 m.
• 61−80 inches - from 7 to 10 m.

So, when choosing a TV, you need to think about its location in the room in advance and select optimal model, based on the layout.

After choosing the TV diagonal, you need to consider the resolution. Here the criterion is the larger the better. Full HD will provide complete comfort and satisfaction from your TV.

The quality of the picture is assessed subjectively. If possible, colors should be natural, without overexposed areas or spots. The image during fast movement should not be jerky, but smooth. The black color must be free of impurities, as black as possible. You should check the transmission of halftones to see if the details are different. The color of the human body: hands, face should be pleasant, without yellow or red spots.

Manufacturers need to be well-known. In addition to the guarantee, this also includes service, as well as the availability of various additional parts and accessories in stores and service centers.

And of course you need to think about additional functions. Do you need Internet access or how important is it to connect your laptop to a large screen?

What is the difference between an LCD and an LED TV?

LED technologies are gradually replacing liquid crystal technologies, since the former are more efficient and economical. This is a serious energy saving and best picture on the screen. Although the differences between these LCD and LED approaches lie only in the way the screen itself is illuminated.

Everything is moving forward. Modern films are produced for latest technologies. Therefore, in order to fully immerse yourself in the atmosphere of the new film, it is better to watch it on LED-TV.

Today, devices with LED backlighting - best solution in terms of image quality and equipment cost. Modern solutions in TVs of this type they allow them to compete with expensive plasmas (PDP), confidently displacing the latter from the market.

True OLED TVs are very promising. In these panels, LEDs are truly the imaging unit. But these models are still expensive and pay for themselves only with very large sizes screen.

Attention, TODAY only!

We make it bright and economical LED backlight from a broken LED matrix (how to make the matrix backlight work without a laptop)

• Closet *

Hi all. I decided to write another post in the sandbox (possibly the last one, it’s starting to seem to me that such topics are not welcome here) and again on the DIY topic in which I want to submit interesting idea, but decide for yourself how to use it. Nowadays, the vast majority of monitors and laptops are equipped with ice-backlit screens (I think few people were surprised when I said this). Often the matrices are broken, and after such repairs I usually end up with a chipped matrix that cannot be restored. We will talk about how to use LEDs and a matrix board to power them.

Of course, you can leave it as a donor, but time has shown that matrices with diode backlighting die extremely rarely (for me, they usually wear broken ones). And the idea occurred to me to use a line of diodes with a standard feeder for my own purposes.

Pros - a fairly bright light source, in theory quite economical (due to the converter), stable brightness, durability, wide supply voltage range (usually from 8 to 19 volts), cons - large electronics board (can be overcome in part, more on that below), Perhaps someone needs to solder. What is a backlight module? This is a line with diodes on which several chains of LEDs connected in series are placed.

And the converter chip itself, located on the matrix board, to which supply voltage and two control signals are supplied - one to turn on the backlight, the second to control its brightness. To turn on the backlight, we will supply power (10-19 volts) and connect the backlight and brightness control pins together and apply 3.3 volts to them. The pinout of the connector is given below. The authorship of this picture belongs to a person from the site rom.by (by the way, all other images are mine and made specifically for this article, but I decided to take the finished one and not redraw it).

We take the common wire from the GND contact, supply power to the LEDVDD and connect inwt_pwm and dispoff# together and supply three volts to them.
We also need a stabilizer to obtain 3.3 volts. In the simplest case, it can be the diagram below. To calculate the resistor, the formula is R = (Usupply-Uzener diode)/Izener diode. We take the average current and the average expected supply voltage. That is, for example, we take an average power supply of 15 volts, a zener diode of 3.3 volts with a stabilization current of 10 mA and we get 1.1 k.
I believe that computer scientists not related to electronics may have problems finding a zener diode - it can be replaced with a TL431 + any low-power silicon diode (in the example 1N4148). Both can be torn out of a dead ATX power supply from a PC. Both circuits are given below. The capacitor, in principle, is almost any 1-10 microfarads. for the second option with tl431, you can not count but take a resistor in the region of 2-3k, and everything works stably. I think that it is even easier to assemble using the second circuit. The circuits are presented below. inwt_pwm and dispoff# on the circuits correspond to PWM and LED_EN, respectively.

The backlight has been launched and you can come up with a use.

But as many will probably rightly note, we have a very inconvenient large board of which we can only use a small part. Unfortunately, here I can only give general advice- call the contacts from the connector to the elements next to the backlight chip, solder the wires to them, make sure that everything works and cut off most of the board hoping for your luck. By the way, I’ll add that the LEDVDD power usually comes to the fuse located next to the converter and the connector for connecting the LEDs, it is usually designated F1 / F2. But control signals can be output to contact pads nearby and labeled as desired, or even present only on the legs of the elements.

And finally, a photo of what I got. Photos turned off and on were taken at the same time, I took the photo automatically, the light is very bright and therefore the photo turned on turned out to be dark background.

And a close-up photo of the redesign of another board. Here I filmed it with my phone - it turned out better.

I will say that I have already tried about 15 boards. One flatly refused to start (it’s possible, of course, that it’s faulty, but I’m mentioning it just in case). The rest started up, two suffered from the fact that I cut the board too short (apparently there were some critical circuits in the inner layers that got into the cut area) and after cutting off the “extra” part they stopped working. For the sake of experiment, I also tried to supply full power to the matrix instead of 3 volts to the control pins in order to reduce labor costs. We took 5 test subjects - two boards failed immediately, two more after a day and a half, one works. Therefore, I abandoned this idea and in all subsequent ones I feed the control conclusions as described above. The article does not discuss controlling the brightness of the backlight - there was no such need yet, so I left it for later.

Application is limited only by imagination - you can make a backlight in the workplace, use it for modding in a system unit, as a backlight in a car and a lot of other things. Well, if anyone has any questions, I will try to advise.

Tags: D.I.Y, LEDs, led, lighting, matrix

LED backlighting in modern TVs with liquid crystal screens today has several technological solutions. In an effort to increase the color gamut to better display colors, TV display manufacturers have developed new backlighting methods that differ from conventional LEDs.

RGB LED

To obtain a wide spectrum of white light, they began to use triads of LEDs consisting of blue, green and red colors in the backlight.

It was an alternative to WLED with a white LED and a smaller color gamut. The lighting system with three different LEDs is called RGB LED. The color gamut of screens with RGB backlighting was greater than those using only white LEDs or using fluorescent CCFL lamps. But there were also disadvantages: price, size, weight, different times LED aging different colors, which over time led to image color detuning. Therefore, we abandoned RGB LED backlighting in favor of WLED.

RGB LED

WLED

Given the shortcomings of RGB backlighting, TV manufacturers have settled on using “white” LEDs. They are located either on the sides of the case or in one array behind the LCD matrix. With the help of special diffusers, the light from the diodes is evenly distributed across the entire screen.

Although we call these LEDs “white,” they actually emit blue light, which passes through a yellow filter and is converted to white. Therefore, the use of white LEDs in screens back in 2010 gave a bluish tint to the image.

Over time, manufacturers have improved the components, and the WLED backlight has become quite functional, but as far as the light spectrum is concerned, some imbalances in the display of colors are noticeable.

This peak in blue is due to the blue LED. Using a filter you can get white light. And this filtered light hits the red, blue and green subpixels to form the entire spectrum of the limited color gamut. Passing through filters, part of the spectrum is lost, and the flux intensity at the frequency corresponding to blue will be greater than at red and green. Using screen calibration you can get correct colors, but these reasons allow the WLED-backlit screen to display colors in only sRGB space.

If a WLED display displays colors in the picture that are close to blue (shades of blue), then the advantage in the spectrum of the blue color may put pressure on other colors that will be mixed to create a tint. Therefore, shades close to blue may not be displayed correctly.

There was a similar problem when using a CCFL lamp, but there the problem was with the green color. It was in green that the peak intensity was visible.

Increased color gamut

To expand the color gamut beyond sRGB and move to the next color standard, changes were made to the WLED backlight.

And after the changes they began to use the name GB-R LED or GB-r LED. Now, instead of a white LED, a combined blue and green LED coated with a red phosphor is used.

This technology allows you to get peaks in the spectrum in red, green and blue.

This technology is used today in LG on AH-IPS matrices and in Samsung on PLS. Using GB-r LED technology, you can achieve 99% Adobe RGB coverage.

Some manufacturers use a different method to increase the color gamut in their screens. They take a mixture of blue and red LEDs and use a green phosphor for the filter. This technology is called RB-LED or RB-G LED.

Hi all. Today we are repairing a Samsung UE32F5000AK with the “no matrix LED backlight” fault. I very rarely repair such TVs, since I have neither the equipment nor the amenities to repair such equipment. But nevertheless, this time I decided to try, and the owner of the TV really insisted.

So let's begin.

Preliminary diagnostics of the TV

When you turn on the TV, there is sound, but no picture. The TV responds to the remote control and buttons. If you look closely, you can see that there is an image on the matrix, but there is no LED backlight. From this we can conclude that the backlight control driver itself is faulty, or some line of LEDs has burned out.

Disassembling the TV

Having decided on possible malfunction, started disassembling. Having placed the TV matrix on the table, the first thing I did was remove the stand, which is held on by three bolts. Next, I unscrewed the remaining 10 bolts around the perimeter, after which I was able to remove the back cover.

When removing back cover, you need to keep an eye on the cable from the joystick, which needs to be disconnected, after which the cover can be set aside.

The TV consists of three boards, namely the power supply, on the board of which the backlight driver is assembled, on the left is the main board, and on the bottom is the t-con matrix control board.

Troubleshooting

IN LED TVs all LEDs are connected in series. This means that if any of the LEDs breaks, the entire LED backlight will stop working. As I said earlier, the main reasons There are two backlight faults: LEDdriver or LEDs.

If the driver is faulty, then for the most part, no voltage is supplied to the LEDs. If the line of LEDs is faulty, then a voltage of about 200 volts will go to the power supply terminal, sometimes it can pulsate from 150 to 200. This indicates that the driver is trying to illuminate the backlight, but there is no load as LEDs, and the driver displays maximum voltage. This process I personally understand it this way.

Having removed the power supply board, I determined that power to the LEDs is supplied through the D9101C to the capacitor, after which I decided to measure the voltage on it. Having connected the multimeter, it turned out that the voltage on it was in the range of 190-210V.

This means that the driver is running idle, and the problem is in the LED line itself. This was not very good news for me, since I am very reluctant to take on disassembling matrices due to my inexperience and lack of conditions for repairs.

Disassembling the LED LCD matrix

With the motto “do no harm,” I began disassembling the matrix. Having prepared the second table on which I will assemble the matrix, the first thing I did was disconnect the cable from the LCD panel to the T-con board. Having examined the structure of the TV in more detail, I saw that the matrix itself is supported by 2 frames, which are attached with latches. I removed the first frame from the beginning. To do this, I placed the TV on the back wall, and gradually, starting from the top, I began to unlatch the latches. I paid special attention to the bottom of the matrix so as not to damage the cables. The top frame came off very easily.

Next, holding the matrix, I placed the TV on the front, with the cables down.

Carefully removed the matrix boards (decoders) from the grooves so that they began to hang freely.

Matrix decoders removed from latches

I’ll say right away that this is such a painstaking process that my nerves were on edge. Having released the decoders from the latches, he took the TV by the second frame and carefully lifted it. The matrix remained lying on the table.

Removed matrix

Having removed the matrix to another table, he continued disassembling. Clicking the second frame, I removed the scattering film and got to the LEDs.

Under the LEDs there is a white reflector, which is held on by 4 locking clips.

After removing them, I was able to remove the reflector.

The structure of LED TV backlighting.

As you can see from the picture, the TV matrix consists of five LED lines of nine LEDs each. If we take into account that each LED is powered by approximately 3 volts, then we have that one line of LEDs uses about 27 volts (3 * 9 = 27). In order to check which LED has burned out, we first find in which line the LED broke. To do this, we alternately connect 27V power to the line of 9 LEDs, and whichever line doesn’t light up is the one that breaks. Next, we connect 3V power to each LED one by one, and look for which LED is not lit.

In my case, it turned out to be very easy to identify a burnt-out LED, since it got very hot, as a result of which the diffusion lens on it changed color and got a little straighter.

The temperature was such that the textolite with reverse side also burned out.

Having pulled out the lens, the LED fell out. For this I used a soldering gun. I applied flux on top of the LED and heated the board from below until it was unsoldered. So I decided to solder the new one too.

Finding a new LED is another task. After going through the radio market several times, I found similar LEDs in one of the stores, albeit already soldered. The man unsoldered them from the TV, on which the matrix was broken.

I also soldered the LED using a soldering gun. Having tinned the tracks, I placed the LED on it with the required polarity, and slowly heated the PCB from below until the LED was soldered. It didn't seal very nicely, as the white paint peeled off, but it was secure.