DIY projection TV repair

It is impossible to imagine a modern apartment or house without video and audio equipment. This equipment is used daily and therefore breaks down more often than others. There are several ways to repair TVs: send equipment to a service center, call a qualified craftsman to your home, or make repairs yourself.

Before you start repairing the TV, you first need to make sure what the problem is. This will help even if you do the repairs yourself, and then when the master comes, you can explain the situation to him.

There are several types of malfunctions that are most often encountered when a TV breaks down.

1. The technology is not turned off. Regardless, a kinescope TV or a modern LCD model broke down, this malfunction is associated with a blown fuse. Only here different models have distinctive details from each other. You should also pay attention to the diode bridge - perhaps it was he who burned out.
2. Both in domestic and imported models, the potential can often go astray, for the function of which the posistor is responsible.
3. If the plasma TV monitor is broken, then the problem, most often, is interference or drops, light or dark stripes may appear, the color changes while watching a program or movie.
4. The problem may be a broken cord or a faulty outlet.

If we take into account all the troubles listed above, it is worth saying that the most difficult breakdown is a screen malfunction. For example, light reflections appear on your monitor after a liquid gets on the matrix or hitting the TV, then it is better to carry it to a teleservice. Here it will definitely be repaired, and if the warranty period has not yet expired, then free of charge or at a reduced price.

See also - How to choose a TV for home in 2018?

You can try to fix some TV malfunctions with your own hands. And it doesn’t matter here whether it’s an LCD model, LCD or LED, it’s not necessary to call a master if you are confident in your abilities. But caution never hurts, because such TV models are not cheap, and without repair experience or knowledge in this area, you can only harm and aggravate the breakdown.

Before you start repairing LED or LCD TVs, you must carefully read the instructions, and also study the principle of operation of your model. Any person, even far from this sphere, will understand that the repair of such TVs as LCD or LED will differ from kinescope models. In the latter case, you are guaranteed not to encounter a faulty posistor. The main thing here is to determine the problem, why does the backlight not work?

If you are repairing LCD, LED models, then the only difference here will be what kind of backlight is used. If this is an LCD TV, then the backlight is made using fluorescent or fluorescent lamps. LED TVs are backlit using LEDs. At this stage, the differences between LCD models usually end.

The breakdown can only consist in the fact that there is no power, in order to check this on the LCD TV, you can do the following with your own hands:

• open the back cover of the model;
• remove the wires connected to the matrix;
• connect a working lamp to the contacts;
• There are also such LCD models in which more than one light source is provided. In this case, all sources must be tested.Just dismantle the matrix and connect your TV to the network - you can see which LED is the problem.

When a broken lamp in an LED or LCD TV is identified, it must be replaced. This stage requires maximum accuracy from the master, as well as the manifestation of special attention. In some cases, the lamp is removed without removing the matrix, you just need to move the protection elements with a rubber gasket and pull out the bulb with a soldering iron. Similarly, it is necessary to mount a working light bulb. Now you can be congratulated - you have repaired the LCD TV with your own hands! Just pay attention to one important nuance - the new light bulb must fully meet the parameters and dimensions of the broken one!

To repair TVs yourself, look carefully at the matrix! If there are “unhealthy” stripes here, then the breakdown lies in the matrix. Have a new item? Then everything is simple! You change it and turn on the TV, if it works, then you have accurately identified the breakdown.

If the reason for the breakdown of LCD TVs is the screen, then it is best to purchase new models of LCD or LED technology. It is not recommended to change the screen of LCD and LED models, as it is impractical! This also applies to the LCD matrix.

What could be the problem with a malfunctioning plasma TV? If you need to repair plasma TVs, then proceed in the same way as described above. Just adapt it to your specific case. This description can be applied to any model of a plasma TV, just stock up on the necessary tool in advance.

Although today most users prefer to use plasma, many still watch programs on older kinescope models. Let's find out how to troubleshoot such TVs. Below is a step-by-step instruction that will help you do your own repair of an electron beam product.

• If you do not turn on such a device, check, first of all, the fuses. In such TVs, the back consists of panels. Therefore, it is necessary to unscrew that part of the panels. Under such a panel you will find a board and you need to connect the power terminals to the fuse. They are connected to an ordinary incandescent lamp, or rather to its base, after which the TV must be connected to the network. In the event that your equipment is working, the lamp will go out after turning on, otherwise, when the fuse is blown, it will either not work at all or will be constantly on.
• The diode bridge may also break. It should only be borne in mind that it is necessary to regulate and repair it only after making a dialing. In this case, not only a multimeter is used, but also a product passport, which indicates the main parameters of this model.
• The most difficult breakdown in a TV with a kinescope is a posistor. To check it yourself, you must first turn off the power circuit, and then turn it on. In this case, you need to monitor the lamp. If the working lamp goes out, then it can be said that the posistor is faulty. To make repairs, you need to adjust the resistance of the network and only venture to change this part.

But not only the matter can be in the posistor, transistors and capacitors burn out in kinescope models. Diagnosis of this breakdown can also be made visually. If the condensate has turned black or cracked, then we replace it with a working analogue. Now you know why the TV does not work and how to fix it yourself.

Repair of a projection TV is a laborious process associated with the large size and features of the TV. So, projection TVs on kinescopes have as many as three kinescopes R, G, B, as well as an information unit and additional information coils.One of the main reasons for the repair of projection TVs on kinescopes is the burn-in of the image when using the still picture function for a long time. In addition, projection TVs are initially set to low brightness, so as a result of prolonged use of an increased brightness level, the phosphor layer may burn out, which will require repair of the TV.
A common reason for repairing a liquid crystal (LCD) projection television is heat dissipation. The principle of operation of such TVs is based on illuminating the crystals with a powerful lamp, from which the matrices heat up and can fail and require repair. Also a common reason for repairing such a projection TV is the rather limited life of the projection lamp, which can be reduced even more if there is insufficient cooling.

Projection TVs advantages and disadvantages

Projection TVs are very popular because they have no equal in terms of the size of the resulting image, in this regard they are champions. In addition, these TVs have an excellent quality image of natural colors.

Projection televisions are classified as elite televisions. The image of such a TV is obtained on a translucent (for projection) and reflective (for projectors) screen. Projection TVs can have a large screen (up to 60″). And the image of the projectors reaches several meters.

According to the principle of operation, such televisions are divided into two groups: front projection televisions and rear projection televisions (rear projection), when the image source is installed behind the screen.

According to the type of image formation source, the following varieties are distinguished: on kinescopes (CRT), on LCD (LCD) matrices, on micromirrors (DLP). In terms of internal structure, all these types of projection TVs are very similar, they differ only in the principle of image formation.

Projection televisions on kinescopes - CRT - models (Cathode Ray Tube). The designs of these models have long been worked out. Typically, these TVs are floor-standing devices, the lower part of which is projection tubes with lenses, speakers and electronics, and the upper part is a mirror and a translucent screen. The image is formed as follows: from three very bright small kinescopes of primary colors, the rays pass a long broken path through a system of optical lenses, mirrors, prisms, hidden in the TV case and projected onto the screen. This leads to a significant increase in the image and this image is displayed on a sufficiently large screen. These TVs have 50Hz and 100Hz scan rates. The advantages here are on the side of 100 Hz models, because they have a more lively, clear and stable picture. This is a very important characteristic, because the image is displayed on a large screen, where errors are more noticeable. The optical system must enlarge the picture from the small screen of the tube and convey it losslessly to the large screen.

The tubes in these TVs must have a high brightness. And this, in turn, creates a large thermal load on the phosphor. This creates the problem of the low brightness of projection televisions on kinescopes. Given this, it is not recommended to leave a freeze frame for a long time, not to increase the brightness excessively, not to run computer games on such TVs, because all of the above can lead to burning of the phosphor, and this will disable the TV. Another negative side of these TVs is the “burn-in” of a stationary part of the image during prolonged viewing.

Designers are constantly struggling with this problem, so modern models have raster screen surfaces with microscopic stripes, which makes it possible to increase the brightness of the image. These surfaces direct the light flux towards the audience.However, this creates the possibility of darkening the image or acquiring a blue tint to it when viewing the TV from the side. Therefore, when choosing a TV model, be sure to pay attention to this.

CRT-models on the screen can form iridescent fringing silhouettes. This is due to the convergence problem, i.e. pictures of 3 colors are not clearly reduced. But this problem has become solvable thanks to the sensors built into the screen for precise alignment of the rays. In some models, convergence is adjusted automatically, in others it must be adjusted manually. But this should be done no earlier than 20 minutes after turning on, so that all tubes warm up sufficiently.

It should also be said that these TVs are much cheaper than plasma and LCD TVs, but they are more voluminous and heavier.

Projection TVs on LCD (LCD)-matrices. Now these TVs are in very high demand. They have three primary color matrices (RGB) or one tricolor matrix. In the LCD screen, a powerful lamp is directed at the image, which forms the image directly on the matrix. The rays then pass through the lens system to the tilted mirror and are reflected on the screen. A beam of light passes through several screens, forming an image: Fresnel screen, designed to turn the beam perpendicular to the plane of the screen; a diffusion screen that enhances the frequency and contrast of the image by absorbing an external light source, through which the image is visible; a protective screen that protects against scratches and mechanical damage.

These TVs attract the attention of buyers with their compactness, small dimensions, relatively low cost. They have a bright large screen, have a high resolution. The image on the screen of such a TV is clear, does not flicker. Image quality is very detailed, which is created by pixels; the analog signal is converted to digital.

The disadvantages of projection TVs on LCD screens include problems with natural color reproduction, a small viewing angle, the problem of heat dissipation of matrices, since a powerful lamp shines through the matrices. Sometimes a "trail" is visible behind moving objects.

Projection TVs on micromirrors (DLP). This is a development of Texas Instruments. The system is based on a microcircuit - a DMD chip, inside which there are about two million micromirrors, each of which forms an image point in a certain place on the screen.

In 1996, this company introduced its digital projection unit, patented under the trademark DLP (Digital Light Processing - digital light processing). This development was promoted to the market in the form of a completely finished optical-mechanical module (Optical Engine), which contained DMD (Digital Micromirror Device) chips, control electronics and an optical system with a light source and a fan. As a result, several models of these projectors appeared on the market, in which there were a different number of chips (1 - 3). The most powerful models contain 3 chips.

What is the principle of operation of these devices? A projection lamp creates a light flux. Light output is measured in lumens. It is certified by the value of ANSI -lm, calculated as the semi-average value of the results of measuring illumination at 9 evenly distributed points of the control screen with an area of ​​0.5 square meters. m at the minimum focal length of the projection lens. This light flux, having passed through a condenser system with a thermal IR filter, mirrors, and a total internal reflection prism, enters a combined beam-splitting prism. This prism separates primary color components from the stream and directs them to the surfaces of micromirror chips of the corresponding channels. The modulated color components reflected by the chips are combined by a combined prism into a common light flux, which then enters the projection lens.

The advantage of DLP projectors is a good overall contrast, the absence of loop lines on the screen, i.e. very clear image contours, accurate color reproduction, high brightness. In addition, micromirrors do not have the effect of flare-up of neighboring black pixels by white pixels, which provides better image contrast and transmission of fine lines. All of the above suggests that these models provide high quality color images.

Three-chip devices are very expensive. It's tens of thousands of dollars. Models with one chip are much cheaper (from three thousand dollars). But this causes an additional load on the viewers' eyes, since a rotating color separating disk is added to the system, on which there are windows sequentially colored in primary colors, and the eye has to perform the color averaging operation, since the image on the entire screen appears sequentially in three primary colors . The frequency of color change in an apparatus with a rotating light filter is about 150 Hz. This may not be sufficient to resolve the above problems. Very few firms own the secrets of creating new single-chip projectors. These are the American company InFocus, the Norwegian Davis, the Japanese Plus.

There are devices on two chips: one is used for red, and the other for the rest. This system is cheaper than a three-chip one. The load on the eyes is reduced, since the sequential transmission of colors is accelerated, the effect of “flashing of the rainbow” is reduced.

The main disadvantage of projection systems is the high price and limited lifetime of the projection lamp (several thousand hours). Since the lamp is powerful enough, it should be well cooled. And this is a fan that can create additional noise. If the supply voltage fails, the lamp overheats sharply, because the fan stops working and the lamp does not cool.

Is your projection TV broken? The question arises, what to do, repair the old one or buy a new one?

How to determine the cost of repairing a projection TV.

You just need to call the above phone number, an experienced master consultant in 80% of cases by phone will determine the cost of repairing your projection TV.

The fact is that projection TVs have their own typical malfunctions.

According to statistics, 8 out of 10 breakdowns are typical. You just need to tell the master the brand and model of the projection TV and describe the nature of the breakdown.

The make and model can be found on the back of the TV. Consultation of the master by phone will help you decide and decide what to do next, buy a new TV or make an application for the repair of an old TV.

For example, the photo shows a sticker from the back of a Samsung projection TV model SP-47Q7HFR.

The most common failure of this model is the non-convergence of the rays.

The image doubles and blurs, it is impossible to converge the rays in the converge menu. The settings don't help.

This breakdown is eliminated by replacing the STK392-040 mixing chips on the AA41-00601C mixing module board.

The photo shows the AA41-00601 board with two STK392-040 information chips that need to be replaced.

Despite the fact that, as a rule, one of the microcircuits fails, it is advisable to replace both; otherwise, after a while, this failure may appear again.

The ST392-040 chip is a three-channel power amplifier. There are 6 amplification channels in two microcircuits, two for each color, red, blue, and green.

Two channels for each color are needed for vertical and horizontal ray correction.

This photo shows three kinescope spotlights on a Samsung SP-47Q7HFR projection TV.

In any case, fixing a projection TV will cost less than buying a new one!

Do-it-yourself TV repair is a responsible business, since today a large number of different models (LCD, LSD, kinescope) are on the market, each of which has its own technological features. Therefore, the approach to each type of TV is individual; in some cases, special skills will be required (knowledge of electronics, experience with a soldering station).

Before proceeding with the repair of television equipment, it is necessary to find out the cause of the problem.

The most common problems:

1. TV screen does not turn on - this can happen with the old kinescope screen and with the most modern television panel. Basically, this symptom is characteristic of a blown fuse. When repairing, you should take into account the fact that for each model you need to select the appropriate fuse. And also experts recommend paying attention to the diode bridge, power supply, wire, perhaps the cause of the malfunction lies in these elements. Read also what to do if the Samsung TV does not turn on.

1. Dim, barely noticeable picture - such a breakdown happens with LCD / LCD monitors. The most likely cause of the malfunction: failed diodes, device backlight.
2. There is no sound, the screen "wheezes" - most likely, the sound amplifier or microcircuit has failed. Read also what to do if there is sound, but there is no image.
3. Monitor lights up, no picture – perhaps the cause of the problem is in the video processor or in the receiving unit.

You should be aware that if a darkening of the board or a break in the elements is detected during a visual inspection of the television equipment, then it is not recommended to immediately start replacing parts. Since such factors indicate a short circuit that could occur in another department of the TV. Therefore, if you do not eliminate the cause of the short circuit, but simply change the failed elements, then the situation will repeat.

The following tools and techniques may be required to repair television equipment:

• Screwdriver Set;
• hex keys (in rare cases);
• pliers;
• soldering station (for repairing modern monitors);
• screen layout (can be downloaded from the Internet);
• multimeter;
• oscilloscope.

Many problems with LCD screens can be completely dealt with on your own. But you should be aware that these screens require more careful handling than, for example, CRT TVs.

First of all, the user needs to study the instructions for his model, and only after that proceed with the repair of the LCD or LED screen. You should know that LCD TVs are backlit with fluorescent bulbs, and LEDs are used on LEDs.

It is possible that the TV does not function due to a lack of power, to check this, you need to follow these steps:

1. Open the back cover of the LCD TV with tools.
2. Disconnect the wires that are connected to the device matrix.
3. Connect a working light bulb to the contacts.
4. Some panels have more than one light source, in which case they must also be tested. You can do this as follows: pull out the TV matrix and connect it to the network, it will immediately become clear which lamp is out of order.

After a faulty lamp is found, it must be replaced. This procedure must be carried out with the utmost care. In most cases, the lamp can even be removed without removing the matrix - you need to move the protection elements and remove the burnt part using a soldering station. Then a new lamp is installed in the same way. An important rule is that the new lamp must be completely identical to the old one.

Another common problem with these models is monitor damage. But in this case, it is not advisable to repair LCD TVs, since it is easier to buy a new screen.This test scheme can also be used to repair plasma TVs of all types. Read also how to fix your own ICE backlight.

Each manufacturer has its own weaknesses, so below is a selection of the most common breakdowns of LCD screens.

Often, users of this brand are faced with such a problem that when the device is turned on, it beeps without interruption. This symptom usually indicates that a leak has occurred. It is recommended that you try replacing the pre-output diode.

Another common problem is the monitor turning itself on and off. The main cause of this breakdown is a failed transistor, it is necessary to replace it. Such malfunctions are recommended to be eliminated independently only by people who have experience in repairing television equipment.

Do-it-yourself Philips TV repair is recommended if the problem is minor: the settings are lost, the cable needs to be replaced.

If the breakdown is complex, then it is better to entrust its elimination to specialists who will not only professionally perform repairs, but also issue a guarantee. Therefore, if the repaired screen stops working again, the user may demand a refund.

Owners of LG flat screens may have trouble saving settings. Such a problem does not require an appeal to the masters; LG TV repair can be done independently. It is enough to transfer the device to another mode of operation, and all settings will be saved.

As well as in the case of other LCD models, if the problem is serious, then do-it-yourself LG TV repair is not recommended, it is better to contact specialists.

Despite the fact that today most consumers prefer the most modern plasmas, kinescope screens are still in demand. These TVs have their advantages: they are inexpensive, easy to operate, and the quality of the transmitted picture is still high.

The main problems of kinescope devices:

• the kinescope TV does not turn on - just like on other types of devices, first of all, you need to check the integrity of the fuses;
• a malfunction of the diode bridge is a common problem for kinescope receivers, you can fix the TV only after performing a “ringing”, you will need a multimeter from the equipment;
• breakage of the thesistor - is considered the most serious problem, in order to check, you need to turn off the power supply circuit of the TV, then start it again. After, observe the lamp, if it goes out, it means that the posistor is out of order. First of all, you need to adjust the resistance of the network, and then replace the part;
• burnout of a transistor or capacitor - such a problem can be easily replaced by visual inspection (black carbon deposits on parts), repairs are carried out by replacing the part.

Below is a list of problems that owners of kinescope TVs face.

1. TV Rubin hums loudly when connected - most likely, you need to replace the photodetector.
2. The ruby ​​does not turn on, the indicator does not light up - voltage surges in the transistor.

1. The Horizon TV does not have a blue tint, and the white balance is also off - this is mainly due to a broken resistor.
2. There is sound, there is no image - the cause of the problem is poor contact in the power connector of the screen board. It is recommended to use a soldering iron to solder the bundle into the Horizon TV board.

1. The screen does not turn on - the problem is with the power supply.
2. A horizontal strip appears on the monitor - repairing a TV hero consists in fixing a problem in the frame scan chip.

Since the failure of the power supply is one of the most common problems of all types of TV, it is necessary to study it in more detail.

Since all models of LCD monitors do not have fundamentally different design differences, therefore, the diagram below can be applied to all TVs (Toshiba, Horizon, Samsung, Sony, Rubin).

Repair of monitors equipped with a kinescope, for example, such as (ruby, sharp 2002sc, sony trinitron, vvk), as well as repair of Samsung TV, Panasonic. always starts checking the power supply.

Testing is performed using an incandescent lamp, but before performing the procedure, be sure to turn off the Sharp c2002sc, Samsung or other screen from the load (line scan cascade). The horizontal scanning voltage can vary from 110 to 150 V, it depends on the size of the kinescope. It is required to find a sweep filter capacitor in the TV circuit. Next, you will need to connect a light bulb, in order to remove the load, you need to unsolder the inductor and fuse through which the JV element consumes power. This scheme is used for sharp screens from 2002sc.

After, connect the power adapter to electricity and measure the voltage, if the values ​​\u200b\u200bare exceeding the norm, you will have to check the feedback circuit of the power supply. If the PSU is in good condition, then the light bulb is removed, and all the elements are soldered in place. This is basic information on how to repair a TV with your own hands.