The appearance of distortions on the screen of a liquid crystal television is most often explained by reasons associated with violations in the functioning of its matrix part (with a backlight failure, for example). In addition, this type of characteristic malfunction is often explained by the failure of the matrix itself, as well as damage to the electronic modules that control its operation.
- Causes of malfunctions and their manifestations
The main reasons for the appearance of well-defined distortions on the screen are:
- Malfunctions of the inverter (backlight converter).
- Burnout of one of the lamps of the screen matrix or its damage.
- Incorrect operation of the entire reproductive system associated with other reasons.
And, finally, the appearance of distortions can be caused by malfunctions of the color block or elements of the motherboard (swollen capacitors, for example).
Important! Most of these malfunctions mainly relate to the matrix elements of the TV.
This once again confirms the importance of careful handling of this work unit. Only a strong impact or deformation of the screen can lead to disturbances in the matrix backlight. Another common explanation for its failure is a strong voltage surge, often observed during the operation of industrial and household networks. The likelihood of this event is especially high in rural areas, where power outages or abnormalities are considered normal. The cause of damage to the matrix can also be an accidental lightning strike into the consumer's power grid, when the lightning discharge penetrates into all household appliances connected to it.
Typical manifestations of each of the listed faults are:
- General darkening of the screen.
- The appearance of alternating colored stripes on it (photo below).
- Small ripples in the picture, traditionally called "snow".
- Image flashes.
- Disappearance of one of the primary colors.
- The appearance of dark spots and spots.
Additional information: Sometimes the characteristic irregularities in the operation of the LCD TV appear as a violent bloom of all colors.
In any of the cases considered, the repair of the television receiver should be started only after the cause of the malfunction has been identified.
Diagnostics and testing
If, when diagnosing a malfunction, the cause of the appearance of distortions was destruction in the matrix itself or in its individual elements, then the only way out is to completely replace the module. But first, it is recommended to once again make sure of the correctness of the assessment made by placing a known good matrix on the TV. The burnout of one of the bulbs of this element is diagnosed by a significant dimming of certain areas of the screen.
In the case when strong ripples or the so-called "snow" are found on it, attention is primarily drawn to the receiving part of the TV (its antenna, cable, or the correct tuning of the channels being watched). When one of the color components (blue, red or green) disappears, it is possible to conclude that there are irregularities in the operation of the unit responsible for their formation or the video amplifier. Testing of this malfunction is carried out in the same way as in the case of the matrix check (replacing the unit that caused doubts with another, obviously working module).
Troubleshooting procedure
The procedure for correcting detected faults depends on the type of the detected problem, which is corrected in accordance with generally accepted methods. So, if one of the matrix lamps burns out, in particular, this element will need to be replaced with a new part.
Please note: If you are not confident in your abilities, it would be more expedient to take the TV to a specialized workshop, where experienced specialists will quickly fix the problem.
In case of mechanical damage to the matrix due to accidental shock, fall or other physical impact, you will definitely have to contact the service. Only with the availability of specialized equipment and measuring equipment will it be possible to replace an inverter, for example, which most often fails in such situations.
If blackouts appear, you should also consult with specialists about the performance of the matrix and the need to replace it. If you find distortions on the screen in the form of characteristic ripples or "snow" (photo above), you should check the reliability of fixing the antenna plug on the rear wall of the TV, and then make sure that the lead-in cable is intact.
Additional information: If all these elements are working properly, you can try to retune the TV channels (from the remote control or from the built-in control panel).
Detection of characteristic blinking on the screen usually indicates that the backlight has burned out. However, sometimes they appear due to problems in the cooling system.
If vertical or horizontal (photo above) stripes appear, the problem should be looked for in the line scan module. Sometimes the cause of this malfunction is the frame scanner. In either case, you will need the help of a repairman.
If unnaturally saturated or inverted colors of primary colors appear on the screen (photo below), the cause of these distortions may be an elementary software failure. To eliminate this unpleasant phenomenon, it is enough to install a fresh version of the program. If one of the primary colors disappears, the chrominance unit is most likely faulty or there may be a video amplifier. The issue is solved by installing a knowingly working module in order to check and replace the failed unit.
When the television picture is completely absent (white screen) with all other components in good working order, you should first replace the failed and swollen electrolytic capacitors on the motherboard. If you find wide stripes of one or two colors at once, try to plug the cable connecting the matrix with the main board, and if there is no result, check its integrity.
