LG TV screen darkened what to do

Tv receiver disassembly

To remove the back cover, unscrew the fastening bolts, after placing the device with the matrix down on the table. After that, you need to act like this.

  • Disconnect the T-con circuit cables and remove the board.
  • Unscrew the metal protection of the decoder and remove it.
  • Unscrew the bolts of the front frame along the edges of the case and remove it.
  • Disconnect and remove the decoder. The matrix must be carefully held by turning the screen over.
  • Loosen the latches and remove the diffusion film.
  • Remove retaining clips, remove reflector.

Having gained access to the backlight elements, they begin to check it.

Possible causes of the problem

On modern TV models, such as LG or Samsung, the TV screen often goes dark if:

  • energy savings are displayed;
  • night mode is always on;
  • the brightness or contrast is incorrectly adjusted;
  • the LEDs or backlight lamps of the screen are out of order;
  • the operation of the backlight control circuit is broken;
  • the inverter driver is faulty (a characteristic darkening of the middle of the monitor appears);
  • the converter module burned out;

So, if only the lower part of the screen of older models (with a thicker body) has darkened, most likely there is a problem with one backlight lamp or its power supply circuit. In newer versions of TV receivers, dimming can be caused by breakage of the LED strips, which illuminate the liquid crystal matrix from the inside. The elements of the tape are connected in series, and when one of them burns out, then the entire tape turns off.

During normal operation, the backlight is supplied with a supply voltage from the inverter (about 200 V). This provides a backlight control LED driver. A disruption in its functioning may also be due to the fact that the TV began to show darker.

The dark screen may not be related to settings or backlighting. The reasons that there is sound, but there is no picture, may be the following factors:

  • defective HDMI cable;
  • the elements in the power supply are out of order, for example, capacitors;
  • the work of the mother (main) board is broken;
  • the matrix itself suffered;
  • problems with the input signal (antenna, TV set-top boxes, cables, connectors);
  • breakdown in decoder, loops or converter.

To accurately determine the malfunction, it is necessary to carry out a complete diagnosis of the device.

The nature of the malfunction and the possible cause

  • you cannot make out what is happening on the screen, the picture is dark and blurry;
  • the image appears for a long time, is distorted and flickers;
  • after turning on the TV, the monitor goes out almost instantly.
  • the picture has lost its brightness and twitches;
  • Forms are not being submitted correctly
  • the image is lagging.
  • ripples and interference;
  • repetition of images and stripes;
  • signal disappears periodically.

The backlight of the liquid crystal polymer layer is faulty:

  • ripples;
  • flashing image;
  • dark display with indistinct or dull silhouettes;
  • the problem occurs on half of the screen.

Darkened TV screen: what to do

If the TV screen darkens, the brightness disappears, the picture becomes dim or disappeared completely, first of all, you should study the instructions and check the device settings. In the event that the TV receiver is adjusted correctly, and the picture is missing or bad, you will have to look for a malfunction.

screen, darkened

How to replace LED backlight bulbs

A burnt out diode or lamp can be detected by illuminating a darkened, dimmed part of the TV screen with a flashlight. In the case when the image has become more noticeable, most likely, the backlight elements of the LCD matrix are faulty.

How to carry out a general diagnosis of the TV

First of all, you need to enter the TV receiver menu, add brightness, check the contrast settings. It is necessary to make sure that the display parameters are set correctly, in accordance with the operating instructions for the device. Next, you need to disable energy saving, if enabled. Also exit night mode if your device supports it.

In addition, before checking the TV itself, you must make sure that the external connections are secure. If possible, replace the HDMI cable. Check that the TV signal source. digital set-top box of terrestrial television, satellite TV. is functioning properly.

If there are several TV receivers in the house, you can check the operation of all peripherals by replacing the TV with a known good one. If everything is in order, you need to diagnose the device itself. To do this, it is advisable to have some skills in radio electronics or entrust the work to the master.

Replacing backlight bulbs

Some breakdowns are easy to identify by the appearance of the failed parts. The presence of deposits, transformations of the color of the lenses or burns indicates a malfunction of the damaged elements.

Lamps are located along the entire perimeter of the screen in horizontal rows or at the top and bottom of the monitor in pairs in pencil cases. It is often possible to identify a faulty element by the characteristic darkening of the cathode. If this fails, you will have to check each one by replacing it with a known good one.

If, after eliminating the identified problems, the backlight does not work as it should, or there are no external breakdowns, then the diode rulers and parts are checked separately.

  • power up all LED strips in turn, controlling their glow;
  • if the semiconductor line does not light up, you will have to find the failed elements by examining each diode;
  • replace the inoperative part with a soldering hair dryer;
  • in case of a critical number of burnt parts, a new tape should be glued.

After checking the functioning of the backlight, the device is assembled.

If the LED diagnostics reveal no problems, the power driver is examined. In this case, power is not supplied to the tape or is in an unacceptable range.

You will need knowledge in the field of circuitry to check the values ​​of the currents and analyze the operation of the power supply.

Advice! After troubleshooting, it is advisable to set the brightness of the LED backlight to 75-80% of the maximum. This will help the lifespan of the LEDs.

Darkening of the TV screen occurs in most cases due to a malfunction of the LCD backlight circuit. You can replace defective lamps or LEDs yourself. First, you should make sure of the cause of the problem by illuminating the display with a bright flashlight. If the lighting devices themselves in the device are in good working order, it is better to carry out further electronics repairs in a specialized service center.

Why TV screen flickers

Flickering of the TV screen is one of the most common problems in modern TV technology. over, in a good half of the cases, the point is not in the device itself, but in an incorrectly connected periphery or a bad signal source. We will find out why the TV screen is blinking, and we will analyze the most effective ways to solve the problem. We will consider modern plasma and liquid crystal devices.

Troubleshooting

If earlier, in order to identify problems, it was necessary to disassemble analog TVs and “ring” the microcircuits for damage, then in the case of modern technology everything is much simpler. To do this, just run a special diagnostic software.

READ  How to Make Screen Video on Android Samsung

For some models (Samsung, Sony, Panasonic, etc.), similar programs are already built into the firmware and run through the menu. The utility will identify the problem in a matter of minutes and offer options for solving it. But in some cases, the programs have to be downloaded separately. For example, on LG TVs, similar software is installed separately from the manufacturer’s official website. It is located in the section “Technical support” in the sub-item “Software”.

LCD TVs

Causes of flickering on the TV:

  • incorrect screen refresh rate;
  • outdated software;
  • burned-out video card;
  • matrix damage.

The first step is to check the refresh rate of the screen in the settings: the TV screen flashes if the value is too low or, on the contrary, greatly overestimated. The optimal frequency for most LCD models is 60 Hz.

To exclude the second point, the device software should be updated. In the TV settings there are sections “Support” (“System”, etc.) and the item “Software update”. Following the instructions of the local master assistant, we perform the procedure and reboot the device.

It is possible to identify points 3 and 4 with the help of third-party programs, but in this case it is not possible to solve the problem on your own without specific equipment and tools. The only way out is to go to the service center or call the master at home.

Cable TV

First of all, you need to inspect the cable for physical damage, and not only in the apartment, but also outside it, right up to the switchboard. If the wires are bare or damaged, then you need to contact the provider with a request to fix the problem.

Another common problem is plug breakage. It is quite difficult to disassemble it, so it is better to find and keep a new one in stock, fortunately, it costs a penny, and it will not be difficult to change it, especially when the cable has already been stripped.

TV signal problems

If the TV screen blinks when the TV cable is connected, then the matter is in the signal source. There may be a malfunction of the antenna, receiver or interface. In a good half of cases, the problem is solved on its own.

Plasma TVs

Plasma technology in this regard is noticeably more reliable, but it can also have problems: the TV screen flashes in different colors, separate areas are illuminated, periodic fading of brightness, etc.

  • the cooling system is blocked;
  • outdated software;
  • damaged video processor.

First of all, it is necessary to inspect and clean the cooling system, because plasma technology has a higher heat transfer rate than LCD models. One of the most common problems is air vents clogged with dust and dirt. It is better to do it thoroughly: remove the back cover and thoroughly blow everything with a vacuum cleaner (for blowing out) or a special cylinder with compressed air.

Plasma TV software is updated in a similar way to LCD technology, through the settings menu. Nothing can be done with a damaged video processor. just change it by a specialist.

Causes of problems

LCD and plasma technology have their own specific characteristics that can cause flickering on the TV. Let’s designate them first, and then we will consider common problems that are relevant for all TV devices without exception.

Plasma screen

Plasma TVs do not have a matrix backlight, so the reasons for the absence of an image are different. This can be burnout of pixels (phosphor layer) due to direct sunlight, dust getting inside the device or failure of the cooling system, etc. To diagnose and identify the cause of the breakdown, you will need the help of professionals.

On LED TVs, a breakdown may be in the power driver of the ice of the matrix backlight or in burned-out LEDs. To determine a breakdown, you need to check the voltage. If the driver is defective, it is missing. If the LED fails, the current is supplied, but due to the breakdown of one link, the circuit opens and does not work. Burnt out diodes are not repaired, but completely changed.

Why LG TV screen may darken

There are a number of malfunctions due to which the screen darkens and the TV receiver stops displaying the picture. They are the same on TVs of different brands and can appear on both LG products and devices from Samsung or another brand.

If, when turning on the LG TV, the user discovers that the screen has become dark, and the picture is practically invisible, the cause of the breakdown may be:

  • defect in the power supply;
  • malfunction of the video amplifier;
  • failure in the matrix backlight;
  • broken t-con controller.

If the power supply fails due to a power surge, poor-quality soldering, swollen capacitors or for other reasons, the TV screen will stop glowing or stripes will be visible on it.

For diagnostics, the device is de-energized and disassembled. Signs of damage are burnt elements, burnt holes, swollen capacitors, etc.

You need to find the damaged unit and fix it, sometimes you need to replace the power supply completely. You can check the part after repair using a multimeter or a connected ordinary light bulb.

If the unit is in good working order, it will light up brightly, then dim and will burn at half the power. If the unit is damaged, the lamp will glow very brightly at all times. The same method will save the microcircuits from damage when connecting a faulty or incorrectly repaired unit.

If the video amplifier fails, the screen darkens, but there is sound. The second sign is a uniform white or green light on the display. You need to open the brightness settings and change this parameter. As a rule, the monitor with such a defect does not respond to user actions.

It is necessary to inspect the damaged unit and check the integrity of the capacitors. Broken elements are replaced, in rare cases, the entire defective part is subject to replacement.
Failure of a T-con board is similar to a malfunction of a motherboard, so it is better to entrust such repairs to specialists. Some TVs are equipped with a special diagnostic function for the T-con board. It is necessary to disconnect the power supplied to it and the LVDS cable.

A test picture will appear on the screen, if there are distortions on it, this means that the part is out of order. In most cases, a complete board change will be required. Sometimes oxidation on the LVDS cable pins can be the culprit for the problem. If you clean them with a regular eraser, the problem disappears.

LCD screen

On LCD TVs with CCFL backlights (fluorescent lamps), the backlight may not work because of blown backlights, broken inverters, broken wiring, etc. To fix the problem, you should contact the specialists.

Matrix malfunctions

If the user sees a dark screen when turning on the LCD TV, the most difficult malfunction is associated with a breakdown of the matrix backlight.
Broken backlighting is the most common cause of dark screens on TVs. To make sure that the reason is precisely this malfunction, you need to check the technique.

To do this, you need to shine a flashlight on the screen. If the image appears, then you will need to disassemble the TV receiver and look for the cause of the breakdown. To repair the TV, you need to contact a professional, an attempt to fix the damage on your own can cause even more damage to the device.

READ  How to adjust the brightness of your LG TV screen

Inverter problems

Inverter may burn out on LG TV. It is responsible for supplying voltage to the backlight lamps, adjusts the image level and brightness, protects microcircuits and boards from overloads, and short circuits.

If the inverter is defective, the display will stop showing light. This means that instead of the video image, the TV will display a regular black screen.

To determine the breakdown of the inverter, you need to conduct a visual inspection of the main components of the TV, which are located on the board under the back cover. To check this component, you need a multimeter. a special device for measuring various electrical quantities.

The inverter can burn out in transformers, lamps or controllers that are located on the lamps. The burnt part must be replaced with a new one. In some cases, the inverter can be repaired. for this you need a soldering iron.

TV repair cost

Conclusion
To understand why part of the TV set screen or the entire monitor does not light up completely, it is necessary to disassemble the TV and run its diagnostics. If you are not confident in your own abilities, it is worth calling for the help of professionals, so as not to cause even more damage to the equipment.

No display appears when LG TV is turned on. Instead of a television picture, a black screen. In this case, the sound is broadcast without any defects. In 90% of cases, the cause of a black screen on an LG TV is a hardware problem. It is difficult to identify the problem on your own, but for people who do not understand technology and boards it is impossible. Therefore, the best solution would be to contact the nearest service center.

In any case, you need to know the main reasons that can become a problem in transferring images to the TV screen of LG brand.

If your LG TV does not turn on at all, we recommend that you first read our instructions.

Checking the LG TV cable

The first step is to check the cable that is responsible for transmitting the video signal (HDMI, antenna, television), and the cable of the Internet provider that provides digital television services.

  • Search for damaged contacts. To do this, you need to remove the sheath. an insulating material made of PVC or HDPE, under which the wires are located. Next, you should diagnose the contacts and the plug (the connector that is inserted into the TV).
  • Using additional software. You can install Monitor Asset Manager (MonInfo) on your computer. The utility detects problems associated with the transmission of video signals to the screen of TVs and monitors. If the program detects a cable malfunction, you need to perform a manual cable check. most likely there are damaged contacts.

LCD screen

On LCD TVs with CCFL backlights (fluorescent lamps), the backlight may not work because of blown backlights, broken inverters, broken wiring, etc. To fix the problem, you should contact the specialists.

Matrix malfunctions

If the user sees a dark screen when turning on the LCD TV, the most difficult malfunction is associated with a breakdown of the matrix backlight.
Broken backlighting is the most common cause of dark screens on TVs. To make sure that the reason is precisely this malfunction, you need to check the technique.

To do this, you need to shine a flashlight on the screen. If the image appears, then you will need to disassemble the TV receiver and look for the cause of the breakdown. To repair the TV, you need to contact a professional, an attempt to fix the damage on your own can cause even more damage to the device.

The matrix cable is damaged

The image on the LG TV may disappear due to damage to the matrix loop. a set of contacts and wires that connect the board that forms the image and the display.

To check the functionality of the loop, you need to perform a visual inspection of the wires. The damaged areas can be re-soldered to help restore the screen to work. At the same time, there is a high probability of repeated failure of the matrix loop.

Therefore, the best solution to the problem is to replace this component with a new one. When choosing a matrix cable, you need to pay attention to the TV model. the part must be original and compatible with the TV brand.

Burnt capacitors

Capacitors can burn out in the TV. they are used to store the charge and energy of the electric field. This problem is especially common with LCD models. One of the reasons for the breakdown of these components is sudden voltage drops.

To determine if the capacitors are faulty, you need to remove the back cover of the TV. All the main components that are responsible for TV operation are on the board. If the capacitors are swollen. slightly increased in size. this means that an urgent replacement of parts is required. Sometimes swollen capacitors explode, which can cause damage to other components on the board.

TV repair cost

Conclusion
To understand why part of the TV set screen or the entire monitor does not light up completely, it is necessary to disassemble the TV and run its diagnostics. If you are not confident in your own abilities, it is worth calling for the help of professionals, so as not to cause even more damage to the equipment.

No display appears when LG TV is turned on. Instead of a television picture, a black screen. In this case, the sound is broadcast without any defects. In 90% of cases, the cause of a black screen on an LG TV is a hardware problem. It is difficult to identify the problem on your own, but for people who do not understand technology and boards it is impossible. Therefore, the best solution would be to contact the nearest service center.

In any case, you need to know the main reasons that can become a problem in transferring images to the TV screen of LG brand.

If your LG TV does not turn on at all, we recommend that you first read our instructions.

TV repair cost

Conclusion
To understand why part of the TV set screen or the entire monitor does not light up completely, it is necessary to disassemble the TV and run its diagnostics. If you are not confident in your own abilities, it is worth calling for the help of professionals, so as not to cause even more damage to the equipment.

Often, when turned on, the user may find that the screen of an LG, Samsung or other TV brand has darkened. The reasons for this breakdown may vary depending on the type of screen.

LCD screen

On LCD TVs with CCFL backlights (fluorescent lamps), the backlight may not work because of blown backlights, broken inverters, broken wiring, etc. To fix the problem, you should contact the specialists.

Plasma screen

Plasma TVs do not have a matrix backlight, so the reasons for the absence of an image are different. This can be burnout of pixels (phosphor layer) due to direct sunlight, dust getting inside the device or failure of the cooling system, etc. To diagnose and identify the cause of the breakdown, you will need the help of professionals.

READ  How to turn on wi-fi on LG TV

On LED TVs, a breakdown may be in the power driver of the ice of the matrix backlight or in burned-out LEDs. To determine a breakdown, you need to check the voltage. If the driver is defective, it is missing. If the LED fails, the current is supplied, but due to the breakdown of one link, the circuit opens and does not work. Burnt out diodes are not repaired, but completely changed.

TV repair cost

Conclusion
To understand why part of the TV set screen or the entire monitor does not light up completely, it is necessary to disassemble the TV and run its diagnostics. If you are not confident in your own abilities, it is worth calling for the help of professionals, so as not to cause even more damage to the equipment.

Why LG TV screen may darken

There are a number of malfunctions due to which the screen darkens and the TV receiver stops displaying the picture. They are the same on TVs of different brands and can appear on both LG products and devices from Samsung or another brand.

If, when turning on the LG TV, the user discovers that the screen has become dark, and the picture is practically invisible, the cause of the breakdown may be:

  • defect in the power supply;
  • malfunction of the video amplifier;
  • failure in the matrix backlight;
  • broken t-con controller.

If the power supply fails due to a power surge, poor-quality soldering, swollen capacitors or for other reasons, the TV screen will stop glowing or stripes will be visible on it.

For diagnostics, the device is de-energized and disassembled. Signs of damage are burnt elements, burnt holes, swollen capacitors, etc.

You need to find the damaged unit and fix it, sometimes you need to replace the power supply completely. You can check the part after repair using a multimeter or a connected ordinary light bulb.

If the unit is in good working order, it will light up brightly, then dim and will burn at half the power. If the unit is damaged, the lamp will glow very brightly at all times. The same method will save the microcircuits from damage when connecting a faulty or incorrectly repaired unit.

If the video amplifier fails, the screen darkens, but there is sound. The second sign is a uniform white or green light on the display. You need to open the brightness settings and change this parameter. As a rule, the monitor with such a defect does not respond to user actions.

It is necessary to inspect the damaged unit and check the integrity of the capacitors. Broken elements are replaced, in rare cases, the entire defective part is subject to replacement.
Failure of a T-con board is similar to a malfunction of a motherboard, so it is better to entrust such repairs to specialists. Some TVs are equipped with a special diagnostic function for the T-con board. It is necessary to disconnect the power supplied to it and the LVDS cable.

A test picture will appear on the screen, if there are distortions on it, this means that the part is out of order. In most cases, a complete board change will be required. Sometimes oxidation on the LVDS cable pins can be the culprit for the problem. If you clean them with a regular eraser, the problem disappears.

LCD screen

On LCD TVs with CCFL backlights (fluorescent lamps), the backlight may not work because of blown backlights, broken inverters, broken wiring, etc. To fix the problem, you should contact the specialists.

Matrix malfunctions

If the user sees a dark screen when turning on the LCD TV, the most difficult malfunction is associated with a breakdown of the matrix backlight.
Broken backlighting is the most common cause of dark screens on TVs. To make sure that the reason is precisely this malfunction, you need to check the technique.

To do this, you need to shine a flashlight on the screen. If the image appears, then you will need to disassemble the TV receiver and look for the cause of the breakdown. To repair the TV, you need to contact a professional, an attempt to fix the damage on your own can cause even more damage to the device.

Plasma screen

Plasma TVs do not have a matrix backlight, so the reasons for the absence of an image are different. This can be burnout of pixels (phosphor layer) due to direct sunlight, dust getting inside the device or failure of the cooling system, etc. To diagnose and identify the cause of the breakdown, you will need the help of professionals.

On LED TVs, a breakdown may be in the power driver of the ice of the matrix backlight or in burned-out LEDs. To determine a breakdown, you need to check the voltage. If the driver is defective, it is missing. If the LED fails, the current is supplied, but due to the breakdown of one link, the circuit opens and does not work. Burnt out diodes are not repaired, but completely changed.

Samsung

Often consumers are wondering why the screen on a Samsung TV turned dark and what to do to fix the breakdown. Appliances of this brand break down for the same reasons as LG devices. To fix the problem, you need to check the power supply, video amplifier and T-con board. If these parts are intact, the malfunction may be related to the matrix.

Samsung Smart TV screen darkened

Recent questions

Samsung UE46H6233 TV, purchased in 2015. Suddenly, the screen immediately dimmed, as if the brightness had been removed. Resetting the settings didn’t help. Economy mode off.

The backlight converter is dead. I’m afraid you won’t do anything yourself. we have such a repair costs 3 rubles

The problem could be with the backlight or the backlight driver. Factory reset won’t help. Contact a service center, it is best to take it to a workshop. This problem cannot be solved at home, since you cannot take all the devices with you, and the master will have to live with you for several days.

Most likely a malfunction in the LED circuit of the backlight of the panel, or in the node of the LED driver. their power converter.

Ice backlight repair about 7000 rubles.

The problem can be both in the power supply of the backlight and in the backlight itself, diagnostics will be required, the base cost of the repair will be 4000r.

This is a matrix backlight problem. Repair from 2500r.

Perhaps one of the locks that fix the loops is not completely closed.
There have been cases when such problems were solved by opening and closing the locks of the loop.
If it is not in the locks, then the problem is hidden in the Electrolytic capacitors in the power supply circuit of the led backlight.