How are LG TVs repaired?

The TV has long been one of the most needed technical devices in any family, because it is he who has been the main source of information for many families for several decades.

One of the most popular brands that produce TVs is the South Korean company LG. The devices of this company are reliable, affordable and have excellent technical characteristics. But, like any other technique, even such high-quality devices can break. Let's try to figure out how you can repair such a TV with your own hands and what kind of breakdowns they have.

If we talk about common breakdowns, then for LCD TVs of this brand, malfunctions of various types will be characteristic. The first problem might be that the device is working but not showing video. There may be several reasons for this:

• malfunction of the matrix;
• breakdown of the power supply;
• failure of the video amplifier or decoder of color signals.

Another fairly common breakdown is the presence of blackouts on the display of the device. The reasons may be:

• malfunction of the high-voltage converter;
• inverter breakdown;
• burnout of the backlight due to physical effects.

If this is typical for all channels, then it is necessary to check the health of the antenna and the cable with which it is connected to the TV. If there is a TV tuner, then there may be a breakdown in it.

Another fairly common problem not only with TVs from LG, but also many others is image flickering. There may be 2 reasons for this:

• it is necessary to replace the backlight lamp;
• the TV is simply overheated.

A slightly different breakdown will be the appearance of such a picture on the screen, as if you are using a thermal imager. It turns out that on the screen one can see as if “petrol” stains. Usually the problem is that either the firmware or individual drivers have crashed. You can reinstall the programs yourself by downloading them from the official LG website and transferring them to a USB drive.

A common problem is the presence of black areas on the screen or spots. The reason for their appearance is the ingress of liquid into the device. Spots on the screen cannot be removed due to the fact that this is a consequence of damage to the matrix. Moreover, replacing the matrix here often does not help, and therefore the only way is to purchase a new TV.

The next common problem is the presence of multi-colored horizontal stripes on the display. There are usually 2 reasons for its occurrence:

• problems with the submodule board;
• swelling of the capacitors located in the power supply.

Horizontal and vertical stripes are also a common problem. The reasons for this are as follows:

• the cable is poorly connected or the connector where it is inserted is clogged;
• the matrix is ​​out of order;
• the TV settings are out of order;
• breakdown of the T-controller, which is solved only by replacing the motherboard;
• burnout or short circuit in the matrix controller.

The problem can be solved replacing them.

The next malfunction is display flickering. From time to time, it can be dissected in wide stripes. If you knock on the side of the device, the situation will improve briefly. The cause of the problem is an unreliable contact between the loop and the connector on the matrix.

If there are large vertical stripes on the screen, then there may be several reasons for their occurrence:

• breakage of the matrix;
• poor-quality contact between the loop and the matrix;
• the problem is in the T-KON board.

Another problem that can be found with LG TVs is the situation when there is sound, but no picture. This can happen because:

• the motherboard is broken;
• the backlight circuit has broken;
• decreased brightness due to hardware settings;
• poor contact of the loop;
• the program has crashed;
• the LED driver has flown, which is responsible for the power supply of the matrix.

Another problem is that the TV simply does not turn on. This can happen due to a breakdown of the power button, a lack of power supply, or a breakdown of the board that is responsible for starting.

If we talk about diagnostics, then as you can see, in most cases, the cause of problems with the device is a malfunction of the matrix or backlight. Suppose it is turned on from the remote control, but nothing appears on the display. At the same time, if you shine a flashlight on it, you can see the image. Then the problem will be either the LED driver or the backlight. And the reason will be that the special lines, where the LEDs are located, could burn out. That is, disassembly is required. It is important to note here that you should open the case of the device only if you understand this. Otherwise, it will be better to trust a specialist.

But in general, removing the back cover from such a device is not difficult. You must first disconnect the legs, and then unscrew the mount around the perimeter of the device.

When the cover has been removed, check the output voltage. If there are no problems with it, then you need to do the same, but with the LED backlight of the screen. If it is at about 100 volts, then this indicates a malfunction of the backlight of the device. To get to the backlight, which is a set of LEDs and special lenses, you first need to pull out the matrix.

Considering that to solve most of the problems, disassembling an LG TV is required, we will give an algorithm for this process. It should be understood that any TV of this type has 3 main boards:

• power adapter;
• basic fee;
• T-Con.

When the cover is removed, the user will have access to them. It should be said that when disassembling this device, you need to be extremely careful and follow a number of rules:

• prepare in advance a place for work and a couple of tables where spare parts will be placed;
• wash your hands before disassembling so that dirt does not get on the filters and the matrix of the TV;
• Dismantling decoders should be done with extreme caution.

If we talk about the steps of disassembly, then there are five of them.

• First, the loops are disconnected, after which the screws that are located between them are unscrewed, disconnected and pulled out the T-Con board.
• We remove metal protection from decoders... To do this, you need to unscrew the fasteners that are located on the sides, as well as the screws. Decoders will have to remain only on rubber mounts.
• Now you need to remove the front frame of the TV... To do this, unscrew the screws around the entire perimeter and put the device on the back panel, then pull out the frame.
• Now we flip the screen while holding the matrix. The decoders should be located at the top so that the rubber mounts can be detached and removed.
• Disconnect the matrix and put it on the tableso as not to accidentally damage it when repairing the backlight.

Now let's try to figure out how the repair of various TV models of the South Korean brand LG is generally performed. Let's start with the plasma models.

If we talk about repairing an LG plasma TV, then everything will come down to a banal replacement of faulty parts and modules with working counterparts. In the absence of any signal on the control buses, it will search for the source, after which it will be necessary to establish the reasons for the disappearance of the signal.

In some cases, for example, when it comes to mechanical damage or when the screen is broken, replacement of damaged parts should be carried out only by specialists who already have experience in carrying out such work.

I must say a little about the problems with the T-Con board, which is the "bridge" between the main board and the plasma panel.... A malfunction of this part will cause a distorted negative or low-contrast image. Here, only an experienced person can do an independent repair, and therefore it would be better to turn to professionals.

If we talk about replacing faulty acoustic transducers or wires and loops, then they can be replaced independently with the same ones. If it is required to repair a pulse-type power supply, then dried electrolytes must be replaced with new ones, because their restoration is also impossible. Here you can do everything yourself.

In the case of LED devices of different inches, it is most often required to replace the LED backlight. More precisely, individual LEDs. To access the tape where they are located, you must first remove the plastic frame and remove the strips that scatter the light... If a diode is damaged, those that follow it will also not burn. Here you just need to replace the LED with a new one. If there are no signs of burning, then you will have to check each one.

But you can avoid this by applying voltage separately to each bar. As a rule, there are contacts for connecting a multimeter. When checking, observe the polarity. If a broken LED is found, it is necessary to first remove the reflective lens to remove it. The bar is usually fixed with double-sided tape, therefore, in order to remove it, you should warm it up with a hairdryer. After that, you should fix the part and warm it up with a blow dryer until the tin holding the lamp melts and it will not be possible to disconnect the LED.

If lenses are dismantled during the work, then it should be taken into account that they are attached using a polymer resin called a compound... She is both insulator and protection. It should be disconnected very carefully and returned to its original place in the same position using superglue.

If the LED just melted, then it can be cut out with a hacksaw with parts of the strip on both sides, after which you should carefully solder the new part in place of the old one. After the repair is over, you should apply voltage to the strips and check their operation. If everything is in order, you can assemble the device.

It should be said that this category of TVs is one of the most common, along with LED models. And the principle of their work is similar in many aspects. Let's say right away: if such a TV, with or without Smart TV support, has received mechanical damage, as a result of which its screen is broken, then it is better not even to try to repair it - you need to immediately look for a new model.

Samples of this type are very susceptible to this kind of damage, and if they receive them, they will eventually fail completely. The difference here will be this: here the backlighting is carried out using fluorescent or fluorescent lamps, and in LED models - by means of LEDs.

So, if it's about the lamps, then it is required to replace faulty ones. Here you need to be as careful and attentive as possible. Depending on the model, the lamp can be pulled out without dismantling the matrix. Here it will be required to very carefully toss the elements with a rubber gasket and dismantle the desired bulb using a blowtorch. In the same way, a similar part can be installed in its place.

After disassembling the device, the power capacitor should be discharged immediately to avoid electric shock or various short circuits. After that, we conduct an inspection for swollen capacitors, burnt parts or mechanical damage.

After that, you should start using the multimeter for the secondary power circuits. The frame scan should also be checked: the transistor and elements in its strapping, chassis and other elements. After that, we check the output circuits of the line transformer, as well as the output voltages. Typically, these TVs suffer from the fact that the voltage of the frame scan is significantly higher than the norm. If this is the case, then most likely the problem is in the capacitor, which, after checking the rest of the elements, should simply be removed from the board. Now it needs to be checked for a large equivalent resistance and capacitance loss.

After replacing these parts, you must turn on the TV and, with the device turned on, make control measurements of the supply voltage on the specified microcircuit. If it is within the normal range, then the repair of the LG CRT TV in this case can be considered complete.

By the way, very often in TVs of this type, the power supply breaks down... To check it, you should use an incandescent lamp. Unplug your TV before performing this procedure. After that, we find the scanning filter capacitor in the TV circuit. Now you need to connect a light bulb to remove the load from it and unsolder the choke and fuse through which the power is consumed. After that, the power adapter is connected to electricity, and the voltage is measured. If its values ​​are more than the standard indicators, then the feedback circuit of the power supply should be checked. If the power supply is working properly, then the light bulb should be removed and all elements should be soldered in place.

In order to prevent recurrence of faults or create unnecessary load on the device, you should find in it such a parameter as the brightness of the backlight. It needs to be set to 75 percent. Then the operation of the device will be carried out in normal mode, it will not receive increased voltage, which will make it possible to significantly extend its operating time.

If we also talk about prevention, then it will not be superfluous to connect the device to the outlet through a special voltage relay, which will save it from surges in the electrical network. This will also extend the durability of the device and make it as safe to use as possible.

Another preventive measure can be called the use of only original components for repairs or those that are most suitable in terms of their technical characteristics to the parts that need to be replaced. This will not upset the balance of all the characteristics of the device and will ensure its stable operation for a long period of time, even after repair.

See below for what to do if your LG TV won't turn on.