The plasma TV has fallen down, there is no picture. The TV has lost the picture, but there is sound: solution to the problem

Users encounter such a failure quite often. Run diagnostics to determine why there is no picture on the LJI TV, but there is sound. Mostly the reason lies in the malfunction of the hardware modules. However, software failures cannot be ruled out either.

Users can fix some defects on their own. More complex breakdowns requiring a complete disassembly of the TV are best left to the specialists of the service center.

If there is no picture on the LG TV, but there is sound, then this is just one of the signs of a malfunction of the equipment. There are other symptoms that also indicate a problem with the TV device. Let's consider the most common defects.

The user can eliminate the defects listed above on his own. Many of the troubleshooting methods described above can also help if there is no picture but there is sound.

Reasons for the disappearance of the image

The most common reason for the disappearance of the image on the LV TV is hardware breakdowns. What to do in such situations? How can I restore the correct broadcast of digital or analog TV? It is necessary to carry out diagnostics to determine the failed module.

Immediately after identifying a damaged component, it must be replaced. You can do this yourself. However, this option is relevant, provided that you have the necessary skills and equipment. If you do not know how to repair a TV, then contact the service center.

Now let's go directly to the consideration of the main reasons for the disappearance of the image.

Burnt out power supply

If there is sound, but the picture is constantly twitching, the screen is dark, the brightness has dropped, other defects have appeared, it means that it does not function correctly.

Users who do not know how LG LED TVs work should never try to repair them on their own. Call a specialist who can quickly determine the reason for the incorrect operation of the TV.

However, the diagnosis can still be carried out independently at home:

1. Start by discharging the capacitors. Unplug the TV from the wall outlet. Unscrew the fixing bolts, and then remove the rear cover. Check cables and cables, some of them may be damaged. Be sure to test the functionality of the buttons and fuses.
2. Inspect the power supply for melted or charred resistors, capacitors. If there are such elements, then they must be replaced immediately.
3. Measure the voltage of the output circuits of the power adapter. The obtained indicators must correspond to the parameters indicated on the board or in the technical documents.
4. Voltage drops. For example, the voltage level reaches 200V, find the cause of the breakdown in the primary power circuit.
5. If you knock on the TV case, and the image returned to normal for a few seconds, then the problem was caused by poor-quality soldering of the power supply elements.

Soldering of contacts and other elements must be carried out with professional equipment. The use of improvised means is fraught with the aggravation of the original malfunction.

Broken cable

If the quality of the audio signal does not raise any questions, and there is no picture, it is imperative to check the integrity of the connecting elements. It's about the cable. Which one? The answer to this question depends directly on the signal source. Therefore, you need to inspect:

• antenna cable;
• HDMI wire;
• cable connected by your cable TV provider;
• Ethernet cable (provided that you are using Smart TV).

Use special software to determine the cause of the black screen. For example, the Moninfo utility. It helps you identify audio and video problems. If the program detects malfunctions, you must carefully inspect the cable for damage.

Failure of the matrix

Matrix breakage is perhaps the most common reason that there is no picture on the TV screen. Also, damage to the matrix can cause a number of other symptoms:

• video shakes;
• the image is displayed only on half of the screen;
• stripes appear around the perimeter of the screen.

Why is the matrix not working? The component fails due to short circuits and mechanical damage. It is impossible to repair a faulty matrix. Therefore, a part is replaced. If defects began to appear for no reason, for example, the image darkened sharply. The matrix elements are probably damaged, their replacement is much cheaper than the entire module.

Can you change the matrix yourself at home? This is theoretically possible. However, it will be extremely difficult for a person who has never repaired TVs. In addition, instead of the broken part, you need to install the original matrix. It is very difficult to buy branded accessories.

Capacitors burnt out

In LCD TVs, capacitor problems are caused by power surges. Signs of a defective capacitor:

• the picture is double;
• there is no image;
• the TV turns off arbitrarily;
• low brightness level;
• incorrect color rendering.

In order for the device to start working correctly again, you need to disassemble it. On the board, you will see a damaged capacitor and a blown fuse.

If the breakdown is not eliminated in a timely manner, the malfunction will worsen. After a while, there will be irregularities in the operation of the power supply. The complex of procedures aimed at diagnostics is identical to the situation with a broken matrix.

Replacing capacitors is a complex type of hardware repair for TVs. The slightest inaccuracy will provoke an aggravation of the malfunction. Therefore, it is wiser to entrust the elimination of the malfunction to the specialists of the service center.

Matrix loop

Sometimes the image on the LG TV disappears due to damage to the matrix cable. Breakage manifests itself in the following signs:

• the image periodically disappears;
• unsatisfactory picture quality - there are noise, ripples;
• horizontal or vertical black-and-white, colored stripes appeared.

The specifics of the elimination of the breakdown will directly depend on the specifics of the damage to the loop. If the malfunction was detected at an early stage, then the service center masters will rewire the damaged sections of the loop, restoring the TV to work. In some situations, you have to change the matrix loop completely.

The second option is considered a more durable solution to the problem. A soldered loop will work for a relatively short time. Therefore, it is wiser to immediately change it to the original component. You should not do this on your own. Entrust the work to professionals.

Burnt out inverter

Due to the fact that the inverter has broken down, the TV screen stops working. Breakdown symptoms:

• distortions appear, the picture twitches;
• the image is missing in principle or takes a long time to load;
• the TV display dims after switching on and instantly goes out;
• sound is transmitted correctly, but ripples appear on the screen;
• the picture is very blurry, the brightness level is low.

The main function of the inverter is to supply voltage to the backlight lamps. Therefore, if the TV screen does not light up, then perhaps the reason lies precisely in the malfunction of the inverter.

The module performs many other functions:

• conversion of direct (12-volt) voltage to alternating;
• stabilization of the input current of the lamp to the required indicators;
• adjusting the brightness level of the image;
• matching the output stage with the input tube resistance;
• protection of microcircuits and boards from possible short circuit, overload.

How to determine if the problem with the absence of an image is caused by the failure of the inverter? It is necessary to disassemble the TV and carry out a comprehensive diagnosis. The failure of the module can be determined by visual inspection.

To restore a TV, you need to have at your disposal a hot air and infrared soldering station, as well as a multimeter. A good knowledge of physics and electronics is also required. It is extremely difficult to say which element has failed. Incorrect TV operation can be caused by a breakdown of the lamp, transformer, board controller.

Inoperative backlight

If the LG TV does not broadcast the image, then the reason may also be a breakdown of the screen backlight. Modern models are equipped with LED backlighting, which provides the highest quality picture. It is extremely easy to determine the breakdown, if the picture blinks or ripples appear, then the cause of the problem is incorrect illumination of the polymer LCD layer.

How can such a malfunction be eliminated? It is almost impossible to do this with improvised means at home. If only because you will not have the necessary parts. You need to order components from authorized distributors. They will have to wait for a very long time. In general, it is a very expensive pleasure.

Therefore, the best way out of this situation is to contact a service center. Certified workshops work with official suppliers. Therefore, they will be able to quickly change the entire backlight or a faulty LED.

If, when switching channels, the images of their numbers are normally visible on the screen, then it is guaranteed to exclude malfunctions of the part of the circuit that is responsible for the formation of the image or the performance of the screen.

The block of the radio channel also makes no sense to suspect, since there are no problems with sound.

Most likely the reason lies in the matching elements between the color signal inputs and the TV processor. Such "floating" faults most often occur with faults in electrolytic capacitors.

It is possible to diagnose a malfunction of a specific capacitor either with a special device (while guaranteeing 100% accuracy of the result) or visually. A serviceable capacitor has a flat cylindrical shape and a flat top end, on which notches are visible in the form of straight lines or in the form of some kind of stigma. A swollen top indicates that the capacitor needs to be replaced.

The second reason for the disappearance of the image is a software glitch. Such a malfunction is eliminated by re-flashing the control processor, but this requires specific equipment and is performed only in a service center.

Samsung's technical support service usually advises in such cases to update the software via an Internet cable. This advice should not be neglected. If the violation does not affect the unchangeable part of the program, then the problem should disappear, otherwise the intervention of the service center cannot be avoided.

The very first televisions are so different from modern technology that there seems to be almost nothing in common between them. In fact, the general principles of operation have been preserved, and some malfunctions of televisions of different models are repaired in the same way. However, there were also new causes of breakdown associated with the features of the screen matrix, with the device of microcircuits and much more.

Problems turning on or off

If the TV does not want to turn on, and the power indicator light does not even light up, then the problems are most likely with the power supply. It may burn out as a result of a large voltage drop.

A similar reason can be when the TV turns off spontaneously. If protection against voltage drop is installed, then it can turn off the device at the right time. If you know that the voltage was stable, then you need to check the power supply and look at the motherboard to see if there are any microcracks in it.

No response to the control panel

This is a fairly common problem, but in most cases it is associated with a malfunction of the remote control itself. Perhaps you dropped it or spilled something on it, so it stopped working. You should also check the batteries to know that everything is in order with them.

It happens that the remote control has nothing to do with it, and the problem is a malfunction of the remote control receiver on the TV or a problem in the processor.

Memory problems

It happens that you want to set up channels and remember them, but nothing happens. This may be due to a problem with the memory device. A similar situation is when you adjust the sound, turn off the TV, and after turning on the settings are not saved. It will be necessary to check the memory chip and, if necessary, replace it.

Buttons on the TV do not work

If you press a button on the TV itself, but no reaction occurs, then you need to check if the contact connecting the button to the microcontroller has broken. If all contacts are intact, then you need to look for the reasons in the controller processor.

Sound problems

The sound problem is caused in most cases by some kind of speaker malfunction. It is necessary to check that they are turned on, connected, all contacts are intact. There are problems with the bass amplifier as well as with the sound processor. In the most extreme case, it is necessary to look for a solution in the operation of the radio channel.

Poor image or no image at all

An annoying situation when the TV turns on, and even a sound is heard, but there is no normal picture. The reasons for this can be very different, but they can almost always be solved. It's another matter whether you can solve them yourself, or you will have to call a specialist.

• When the picture is completely absent, and the sound is excellent, this may be due to a malfunction of the matrix or video amplifier.
• No picture and intermittent audio dropouts may indicate that there is a scan problem.
• If there is sound and the screen glows, but does not show anything, then there are some problems with the video processor. It could also be caused by interference in the tuner.
• An annoying situation when the image is rotated only half (bottom or top) of the screen. This indicates a malfunction of the vertical scan of the matrix. The vertical scan module fails due to power surges and poor performance of the power supply.
• If a narrow vertical strip appears on the screen, then something is wrong with the horizontal scan transformer, if the horizontal strip is horizontal, there are problems with vertical scanning.
• The image has become one color or one color has disappeared. This indicates that the video processor or video amplifier is broken.

Individual faults of the matrix

In a modern TV, a malfunction of the matrix becomes a big problem that can only be solved by replacement. The matrix, in fact, is a screen, or rather, its main part, on which the image is built. The reasons for the failure of the matrix can be the following:

• being hit by a hard object or being dropped;
• ingress of moisture on the matrix contacts;
• manufacturing defect, electrical defect;
• wear as a result of long-term work.

Due to damage to the matrix, multi-colored stripes, black circles may appear on the screen, image fading or its complete loss may occur. Only a specialist can diagnose and replace the matrix, since there are many features of connecting and configuring the device.

Sweep problems

There are several indicators that indicate that there are problems with the vertical scan of the TV:

• the image has decreased or shifted vertically;
• centering was disturbed;
• lines appear on the image, indicating the return path of the rays;
• there is no frame scan at all, etc.

In the absence of a vertical scan, one horizontal luminous strip is visible on the screen. Typically, all these malfunctions are associated with improper operation of the vertical generator unit. In the generator, the frame rate is set by capacitors, resistors, diodes, transistors. If the TV is with a kinescope, then the signal from the frame scan unit is fed to the deflecting system. There may be problems with the contacts, a breakdown may occur in the deflecting system.

Only a person who is well versed in the TV device can fix the problems of all these elements, so contact the service center.

From all that has been said, it is clear that most problems can be eliminated only at a service center. On our own we can:

• check if there is voltage in the network if the TV does not turn on;
• check the contact of the antenna connector, whether it is well connected, try to tune in other channels, if the image is not of high quality;
• if there is no sound, see if the headphones are plugged into the jack, unplug them, plug in and out again, make sure the sound setting is correct;
• replace the batteries in the control panel, check its serviceability.

By the signs that we described in the previous sections, you can determine how serious the problem with the TV is. After that, you can call the master or take the device to the service center.

Modern TVs, both SMART and simple LCDs, are complex mechanisms, therefore the user needs to have more and more knowledge to configure new models.

These devices can have different problems, not only hardware, but also software. A typical example of such a breakdown is a situation when the TV (LCD or) has lost the image, while the sound is on and it is possible to adjust it using the remote control.

Types of malfunctions

It is worth noting that the absence of an image in this case can manifest itself in different ways, depending on the reason / that caused such a violation or change.

Within the framework of this material the following situations will be considered:

1 There is nothing on the screen at all, it does not light up, the TV looks like it is turned off;

2 The picture is changed, distorted, the most common situation- it is narrowed to a strip (at the same time, this can happen constantly, periodically, from the very beginning of work, or only some time after switching on;

3 In some cases, a color screen appears(usually green, white or red), it is monochromatic, the image and any changes on it during work do not appear;

4 There is a picture, but the brightness has dropped so much, that it is almost impossible to distinguish it, while there are no other problems;

5 There is strong ripple or other interference that make it impossible to view content;

6 The image flickers, blinks, brightness and luminous intensity change, which can occur both periodically and throughout the entire operating time, both immediately after switching on, and some time after it.

It should be borne in mind that the image quality, the tendency to breakdowns and the repair features practically do not differ for matrices of different types.

Therefore, it is impossible to reduce the likelihood of such a breakdown in the future.

Breakage nature

Depending on the type of change / violation of the image, it is possible to determine, although approximately, what caused it.

Usually, if we are talking about a not completely extinguished screen, but a violation of the image, then reasons may be as follows:

• It is worth talking about problems in the antenna and signal in the case when there is interference on the screen. If the signal is stable, and everything is in order with the antenna, then the breakdown lies in the radio channel or tuner;
• If both the image and the sound have disappeared, then the matter is most likely also in the radio channel and the tuner, and in addition, video processor;
• A drop in or out of saturation in an image to an indiscernible level may speak (in addition to backlight malfunction) about breakdowns in the color block and video amplifier;
• If there is a bar on the screen, the image does not match the display size, then problem in frame scan and power surges;
• A similar problem is line scan transformer breakdown, which is manifested by the presence of a vertical (whereas in the past case - horizontal) stripes. Sometimes the image is narrowed from top to bottom;
• Full one-color filling of the screen or the disappearance of any color indicates a breakdown in the video amplifier or video processor.

Self-repair can only be carried out if when the cause of the breakdown is fully and reliably established. To do this is sometimes quite difficult in the given conditions and without proper equipment.

Table 1. Types of malfunctions

Diagnostics

How to determine what exactly is broken? Usually, they start checking with the most probable - from the power supply.

If it functions normally, then it is necessary to check the inverter and backlight lamps, update the contacts.

If all these systems are working normally, then you need to check the vertical or line scan unit for serviceability.

Although in case of malfunctions in these systems, the screen, as a rule, still gives some "signs of life", nevertheless, some problems in these systems can be characterized by its complete extinction.

If these systems are also working, then there is a problem in the video path.

In the case when all the equipment described above is working properly, a malfunction, almost certainly, appeared in the system.

It can appear as a result of wear, depletion of the resource or external factors.

Check the functionality of the TV as a whole- whether the remote control, buttons on the TV itself (if any) work, whether these manipulations somehow affect the image or sound.

Repair

Before starting the intervention make sure that you have the necessary skills, tools, equipment and capabilities to interfere with the hardware of your TV. If something is in doubt, then it is better to call the wizards from the service.

Inverter

This is a device for supplying energy to lamps, starting and turning on the backlight. It can be made in the form of one or two complex chip blocks. you can find it on the same board as the power supply.

Before starting the repair, make sure that the incoming voltage is stable and there is no ripple.

After that, see how the command goes to the start of work (start the lamps) with. Often the problem lies in this stage.

If it is not detected, then try replacing the backlight lamps themselves with something equivalent. If the system works properly with other lamps, then they only need to be replaced.

If the problem persists with other lamps, then the problem is more complicated.

Standard diagnostic processes are extremely important - measuring voltage, resistance, capacitance using special devices.

A careful visual inspection of the board is also important, since burnt links can be visually noticeable.

Very often, field-effect transistor switches fail, however, replacing them may not bring results or improve the situation for a short time, after which the image will disappear again.

This is due to the fact that the replacement eliminates the effect, but not the cause, and therefore key breakage can occur again.

High-voltage transformers are considered the "weak point" of inverters, since these parts of the device are heavily loaded, therefore they quickly wear out.

Replacing them will often solve the problem.

Lamps

If during the inspection of the inverter it was found that the breakdown is in the lamps (since everything works fine with others), then the easiest way would be to replace them.

The malfunction may arise from external influence on the TV, burnout of the cathode, etc. Replacement is relatively easy with the skills.

At the entrance of this process, it is not even necessary to open the matrix itself - the service masters work with special devices that allow you to turn them off, avoiding even getting dust inside.

If you do not have such a tool, you will have to detach the matrix, which must be done very carefully.

It is worth noting that manufacturers declare that the lamp must be replaced only together with the matrix. You can find the lamp in the reflective container block.

However, often, when disassembling the device, it is noticeable visually.

Disconnecting it must be extremely careful., as it can be glued to other components of the system, and due to high operating temperatures, it sometimes "sticks" to neighboring components.

Find the wire that goes from the lamp to the board. Disable it, remove it and install a new one. Be sure to secure the new lamp using the same methods and locations as the old one.

Power board

For small TVs, it is usually made in the form of a separate unit, for large TVs it is built into the television chassis. Fold back the board and disconnect the unit.

Inspect it carefully, since some problems are visible visually, and take the necessary measurements.

Most often, the problem lies in the filter capacitors, since they are - "weakness" these blocks. After replacing the power supply unit or its parts, connect the lamps and the inverter to it.

The TV has lost the picture, but there is sound: solution to the problem