Television receivers confidently occupy a leading position in the use of among other appliances. They are used by all family members, both in educational purposes as well as for entertainment.
In one family of TVs may be several. In the living room, kitchen, bedroom and so on.
Such popularity of these devices due to the presence in them of a large screen, compared with monitors, provides a more comfortable viewing of video content.
In addition, not all love and know how to use a computer, especially the elderly. Therefore, with the advent of the Internet, all TVs are also popular among different ages and backgrounds.
As with any home appliances, TVs, sooner or later break down. Therefore, it would be useful to know the causes of failures of these devices in order to prevent them, and if it is still happened, try to repair the unit yourself.
Just want to point out that the TV - this is a very complicated and fragile appliances. Treat him to be very careful. This is due to the fact that it is installed CRT or liquid crystal panel, which when careless handling can damage and then replacing them can cost 70% of the cost of the TV. Therefore, we must be extremely careful with them.
As mentioned above, there are two main types of screens in televisions. This is an electronic ray tube (CRT or CRT alias) and a liquid crystal panel.
Ray tube, in its essence - a large vacuum tube, inside which there is a vacuum in which the beam draws the image using the horizontal and vertical deflection coils. In view of the fact that it has an elongated shape, the thickness of the TV is quite significant.
LCD panels are deprived of all this. The panel is a set of LEDs of three primary colors and adjacent to each other.
The image is obtained by applying to each LED voltage from the video processor and depending on the value of different colors and shades are formed on the screen. The use of liquid crystal panels has significantly reduced thickness, weight, and power consumption of televisions.
We can say that it is quite different in the design of the device. The only thing they have in common - is the receiving part of the scheme, is responsible for the sound and controls.
In this article we will focus on the repair of the TV with a cathode ray tube, or CRT, as they are still active, and to repair such a device more chances than LCD.
But in the repair of these devices need to be very careful, because they provide a high voltage of up to 25 thousand volts required for operation of the picture tube. What indicate warning signs pasted on the inside of the picture tube. This voltage may remain on the pipe, even after disconnecting from the network TV.
So you should be careful and attentive not to get discharge current life-threatening. But more on that later.
Let's look at the "symptoms" of breakage TV Rolsen model C29R70T.
It should be noted that the receiver is assembled from components and Samsung's and Philips, indicates a similar skhemoreshenie and other TVs of this type. This means that the causes, and repair vehicles of other companies, will be produced by the same procedure as it is here.
And so, we turn to the most damage, namely, how it manifests itself (see. Figure 2). First, the TV worked fine, but the image disappears from time to time, the screen goes black, and in the middle was a white horizontal stripes. In this case, sound, remote control and other functions operating normally.
Also, no extraneous sounds in the form of crackling and the smell of burning was observed.
Over time, the image is lost at all, but instead are constantly present light bar in the middle of the screen.
It is noteworthy that if the tapping of the TV housing, lane abruptly expanded in synchronization with the punches.
Everything pointed to the fact that somewhere there is a good contact. Now you need to find where.
It is important to determine the possible damage of the "symptoms" to limit the search area and not spend time working TV units. Especially because excess dismantling, removal and rotation of the board connectors can cause more problems than they were before.
For example, it may break off some wire, and there is the danger of "carry" with your hands or with a screwdriver one of the fragile radio components on the board.
Therefore, it is important to conduct a preliminary diagnosis as possible.
As if there were not, the TV will still have to disassemble. Therefore, we proceed to dismantle the rear cover plate.
To determine where the fastening screws, you need to carefully examine the cover on all sides.
Screws can be hidden so that they can be immediately ignore. And one does not otkruchenny screw, will not cover removed, and even when this is possible to break the mounting location.
Moving and turning the TV, it is impossible to shake violently and hit. This can lead to breakage filament yarn in a flask picture tube, which will lead to its failure and the lack of need to repair the appliance on. Of course, in cold spiral that happens very rarely, but it happens sometimes.
So found the screws, unscrew them left. As can be seen, the screws may be in secret places.
One of the most uncomfortable, appeared at the bottom, below the TV. To reach it, you need to lift the rear part of the housing and unscrew the screw. Better to do it together, that one was holding the TV, and the other person to unscrew the screw.
The fact that the front part, where the picture tube, weighs more than three times than the back. Therefore, when trying to tilt the TV to one behind, he can kuvyrknutsya forward so that you do not have time to do anything.
If you still have not found a partner, you can put in front of several weighty books. This will give a TV stress when trying to tilt.
When all the screws on the perimeter of the cover are unscrewed, trying to pull her back. That it is better to come out of the slots, the TV must be tilted slightly forward.
Remove the cover, taking care that it does not change its direction of motion. If it abruptly move aside, it can break the picture tube flask on which a board with elements.
Vial in this area is very fragile and has a significant narrowing. Also, when the cover has to be removed, care must be taken not to hit or catch the flask.
You do not need to touch and shift levers setting beam deflection, or later the picture may not be clear, and return them to their original position without special devices will not work.
Remove the cover and put it aside. When viewed with the naked eye can see, how much dust inside as on the body and on the boards. If possible, it should be wiped. This dust becomes conductive and can cause a short circuit or even a fire.
Due to the high voltage inside, all the dust is drawn from the room and settles near the high voltage converter elements.
Over time, through it may be backache current TV chassis. Therefore, the dust must be removed.
Even the manufacturers recommend doing this at least once a year.
Take rag wipe and housing both outside and inside.
One can see how much dust has accumulated on the surface for a couple of years.
Charge is also desirable to clean (see. Figure 13). But not with a damp cloth and cotton wool soaked in alcohol.
As pollution wool needs to be changed. Even this can be done with a vacuum cleaner with a special nozzle in the form of a brush. In any case, you need to clean the board carefully and slowly, so that nothing is broken.
Dust-free motherboard will be better cooled, which would prolong the operation of its components.
Proceed to troubleshooting. View to the main board in the presence of burning tracks and electronic components. To understand where to find the problem, you need to know of any conditional blocks is "filling" of the TV, and what components are responsible for what.
CRT TVs with the latest models are based on single-chip processor. Basically it is the Philips chip. Signal from antenna port reaches the channel selector, where it is converted.
Further, the signal having passed some of the filters is supplied to the single-chip processor. There also receives signals from the "tulip" type connector and Scart.
It is processed and broken down into the audio, video and impulses necessary to operate the CRT sweep.
Each of the signals coming out from a specific processor output.
Further, he or amplified by means of special circuits, or sent directly to the execution unit.
Signals are amplified: a low-frequency (audio), video, pulses frame and line scanning. For each signal has its own amplifier, built mostly on the chip. Therefore, a good idea to have a schematic diagram of the TV, which can be found on the Internet.
Use the search Yandex, you can determine which chip is responsible for what.
So it will be easier to find the cause of the damage, paying special attention to the respective block components.
Let's go back to our TV. Let us make a fault analysis. The sound is, the channels are switched, then: the power supply, tuner, amplifier and sound processor in order.
We draw attention to the fact that the screen is a horizontal bar in the middle. This indicates improper operation of vertical deflection.
If the strip is vertical, attention needed to be paid to the elements of the horizontal scanning and the high voltage transformer.
And so, the problem of a small amplitude vertical deflection signal. This signal is too small to sufficiently deflect the electron beam human coils.
So, the problem is likely in the amplifier of the signal. Using found online scheme to this TV, it was determined that this chip TDA8359J. She has nine pins, and it is located on a common heat sink - the heat sink.
The board will be identified as the D600.
Perhaps it is out of order, or tying - resistors and capacitors. Carefully inspect the chip itself and a number of elements arranged to change the color or bloating. Nothing like this can be seen.
Next, pull the card closer and overturn it. Here can be seen the tracks and solder joints. For a good result, it is desirable to use a desk lamp and magnifying glass.
Also, you should be careful not to touch the places rations of high-voltage electrolytic capacitor, not to get bit.
It can be a screwdriver to short-circuit terminal of the capacitor to discharge and work quietly.
Upon closer inspection, through a magnifying glass, seats soldering legs D600 chip, a defect in the form of tin crack was found, around the output circuit (see. Figure 21). I notice it is very difficult, especially with the naked eye.
This defect is very common in different techniques. The reason are: low quality tin thickened stem parts and considerable heat during operation. No wonder, the chip has a heat sink.
Another cause may be the vibrations, and a thin glass fiber from which payment is made. The manufacturer saved on the thickness of the material, as a result, we have a problem. The board is really easy to bend, which leads to cracks rations, peeling tracks and other defects.
The output from such a situation becomes a meticulous welds all the legs of the chip. Be sure to use a soldering flux. In no case do not use acid, but only rosin.
Solder can be legs and other power circuits and bulky components.
Solder terminals processor is not recommended without need. Since they are too close, they can be easily overheat or short legs together. Then it all back will be very difficult.
After soldering, a knife or something sharp, clean mikrosoedineniya possible paths between the board, especially where the work was done.
Install the card back and try to turn on the TV. It is desirable to put on the cover, taking care not to damage the picture tube, you will need to hold back Scart connector to charge entered in the seats.
As seen in the picture, the picture is reversed for the whole height of the screen, and it means that the problem was just in the cracks in the soldered feet of vertical deflection circuits.
You can now fasten the cover screws and use the TV on.