DIY projection TV repair

It is impossible to imagine a modern apartment or house without video and audio equipment. This equipment is used every day and therefore breaks down more often than others. There are several ways to repair TVs: send the technician to a service center, call a qualified technician at home, or make repairs with your own hands.

Before you start repairing a TV, you first need to make sure what the problem is. This will also help if you do the repair yourself, and then when the master comes, you will be able to explain the situation to him.

There are several types of malfunctions that can most often be found when a TV breaks down.

1. The technique does not turn off. In independence, a CRT TV or a modern LCD model has broken down, this malfunction is associated with a blown fuse. Only 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. In both 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, 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 considered to be a screen malfunction. For example, light reflections appear on your monitor after the liquid hits the matrix or the TV is hit, then it is better to carry it to the teleservice. Here it will certainly be repaired, and if the warranty period has not expired, then it will be free of charge or at a reduced price.

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

You can try to fix some malfunctions of TVs yourself. And it doesn't matter here - these are LCD models, LCD or LED, it is not necessary to call the wizard if you are confident in your abilities. But caution never hurts, because such TV models are not cheap, and without having any 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. Anyone, even one far from this field, will understand that the repair of TVs such as LCD or LED will differ from CRT models. In the latter case, you are guaranteed not to run into a faulty PTC thermistor. 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 it is an LCD TV, then the backlighting is produced using fluorescent or fluorescent lamps. For TVs, LED backlighting is produced using LEDs. At this point, 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 an 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 the working lamp to the contacts;
• there are also LCD models in which more than one light source is provided. In this case, all sources must be tested.Just dismantle the matrix and plug your TV into 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 care 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 protective elements with a rubber gasket and pull out the lamp with a soldering iron. Similarly, it is necessary to mount a working light bulb. Now we can congratulate you - you did the repair of 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" streaks here, then the breakage is in the matrix. Have a new part? 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 equipment. 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 it is necessary 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 plasma TV, just stock up on the necessary tools in advance.

Although today most users prefer to use plasma, many still watch programs on more outdated CRT models. Let's find out how to repair a breakdown in such TVs. Below is a step-by-step instruction that will help you repair your electron beam product with your own hands.

• If you do not turn on such a device, check first of all the fuses. In these TVs, the back is made up of panels. Therefore, it is necessary to unscrew that part of the panels. Under such panels you will find a board and the power terminals must be connected to the fuse. They are connected to a conventional incandescent lamp, or rather to its base, after which the TV must be connected to the network. In the event that your equipment is in good working order, the lamp will go out after switching on, otherwise, when the fuse has blown, it will either not work at all, or it will constantly burn.
• 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 dial. 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 with your own hands, you must first turn off the power circuit, and then turn it on. In this case, the lamp must be monitored. If the work lamp goes out, then it can be said that the posistor is faulty. To make repairs, it is necessary to adjust the resistance of the network and only ventures to change this part.

But not only the matter may be in the posistor, transistors and capacitors burn out in CRT models. The diagnosis of this breakdown can also be made visually. If the condensate is blackened or cracked, then we replace it with a serviceable 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 televisions on kinescopes have as many as three kinescopes R, G, B, as well as a block of information and additional information coils.One of the main reasons for the repair of projection TVs on CRTs is image burnout during prolonged use of the still picture function. In addition, in projection TVs, a low brightness is initially incorporated, therefore, as a result of prolonged use of an increased level of brightness, the phosphor layer may burn out, which will require repair of the TV.
A common reason for repairing a Liquid Crystal Display (LCD) TV is heat dissipation. The principle of operation of such TVs is based on the illumination of crystals with a powerful lamp, from which the matrix heats up and may 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 further reduced 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 excellent picture quality in natural colors.

Projection TVs are classified as elite TVs. The image of such a TV is obtained on a transmissive (for projection) and reflective (for projectors) screen. Projection TVs can have large screens (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: televisions with front projection and televisions with rear projection (rear projection), when the image source is installed behind the screen.

By the type of source of image formation, the following varieties are distinguished: on picture tubes (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 picture formation.

CRT - CRT models (Cathode Ray Tube). The designs of these models have been worked out for a long time. Typically, these TVs are floor-standing devices, the lower part of which is projection tubes with lenses, acoustic systems and electronics, and the upper part is a mirror and a transmissive screen. The image is formed as follows: from three very bright small CRTs of primary colors, the rays travel a long, broken path through a system of optical lenses, mirrors, prisms hidden in the TV case and are projected onto the screen. This leads to a significant increase in the image and this image is displayed on a large enough screen. These TVs have 50Hz and 100Hz scan rates. The advantages here are on the side of 100 Hz models, since they have a more vivid, 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 bring it losslessly to the large screen.

The tubes in these TVs should 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 CRT TVs. Considering 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, since all of the above can lead to burning of the phosphor, and this will damage the TV. Another negative side of these TVs is the “burn-in” of a fixed part of the image during prolonged viewing.

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

CRT models may have rainbow silhouette borders on the screen. This is due to the problem of mixing, that is, pictures of 3 colors are not clearly brought together. But this problem has become solvable thanks to sensors built into the screen for precise alignment of the beams. In some models, the convergence is adjusted automatically, in others, it must be adjusted manually. But this should be done no earlier than 20 minutes after switching on, so that all tubes are sufficiently warmed up.

It should also be said that these TVs are much cheaper than plasma and LCD TVs, but they are bulkier 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 tri-color matrix. In an LCD screen, a powerful lamp is directed at the image, which forms an image directly on the matrix. The rays then travel 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: a 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 through the absorption of an external light source, through which the image is visible; protective screen that protects against scratches and mechanical damage.

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

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

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

In 1996, this company introduced its digital projection unit, patented under the DLP trademark (Digital Light Processing). This development was marketed as a fully finished 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? The projection lamp creates a luminous flux. Luminous flux is measured in lumens. It is certified by the ANSI-lm value, calculated as the weld mean of the results of measuring the 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 luminous flux, passing through a condenser system with a thermal IR filter, mirrors, a total internal reflection prism, enters the combined beam-splitting prism. This prism separates the components of the primary colors from the stream and directs them to the surfaces of the micromirror chips of the corresponding channels. The modulated color components reflected by the chips are combined by a combined prism into a total luminous flux, which then enters the projection lens.

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

Three-chip devices are very expensive. This is 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 separation disk is added to the system, on which there are windows sequentially painted in primary colors, and the eye has to perform the chromaticity averaging operation, since the image on the entire screen appears sequentially in three primary colors ... The frequency of changing colors in a device with a rotating filter is about 150 Hz. This may not be sufficient to remedy the above problems. Very few firms own the secrets of creating new single-chip projectors. These are the American company InFocus, Norwegian Davis, Japanese Plus.

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

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

Is your projection TV broken? The question arises, what to do, fix 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, 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 viewed on the back of the TV. Consulting a wizard by phone will help you decide what to do next to buy a new TV or make a request to repair an old TV.

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

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

The image doubles and fuses, it is impossible to converge the rays in the information menu. Settings don't help.

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

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 microcircuit 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 picture tubes of the Samsung SP-47Q7HFR projection TV.

Either way, fixing a projection TV is cheaper than buying a new one!

Do-it-yourself TV repair is a responsible business, since today a large number of different models (LCD, LSD, CRT) are presented 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 are:

1. TV screen does not turn on - this can happen with an old picture tube screen and with the most modern television panel. Basically, this symptom is characteristic of a blown fuse. When repairing, it should be borne in mind that the appropriate fuse must be selected for each model. 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 Samsung TV does not turn on.

1. Faint, barely noticeable picture - such a breakdown happens with LCD / LCD monitors. The most likely cause of the malfunction: faulty diodes, device backlighting.
2. There is no sound, the screen "wheezes" - most likely, the sound amplifier or microcircuit is out of order. Also read what to do if there is sound, but there is no picture.
3. Monitor is on, 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 rupture of elements is detected during a visual inspection of television equipment, then it is not recommended to immediately start replacing parts. Since such factors indicate a short circuit that could have occurred in another section 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 itself.

To repair television equipment, the following tools and equipment may be required:

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

Many LCD screen problems can be dealt with on your own. But you should know 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 start repairing the LCD or LED screen. You should be aware that LCD TVs use fluorescent bulbs for backlighting, while LEDs use LEDs.

The TV may not function due to lack of power, to check this, you need to do the following:

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 be tested as well. This can be done 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 the faulty luminaire is found, it must be replaced. This procedure should be carried out as carefully as possible. In most cases, the lamp can be taken out even without removing the matrix - you need to move the protection elements and get the burned out 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 damage to the monitor. 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 televisions of all types. Read also how to fix the LED backlight yourself.

Each manufacturer has its own weak points, so below is a selection of the most common LCD screen breakdowns.

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

Another common problem is that the monitor turns on and off itself. The main reason for this breakdown is a failed transistor, it is necessary to replace it. It is recommended that such malfunctions be eliminated on their own only by people who have experience in repairing television equipment.

DIY Philips TV repair is recommended if the problem is minor: settings are lost, cable replacement is required.

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.

LG flat screen owners may have a problem saving settings. Such a problem does not require contacting the masters, you can repair the LG TV yourself. It is enough to switch the device to another operating mode, and all settings will be saved.

As well as in the case of other LCD models, if the problem is serious, then it is not recommended to repair an LG TV with your own hands, it is better to contact a specialist.

Despite the fact that today the majority of consumers prefer the most modern plasmas, CRT 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 with CRT devices:

• the CRT TV does not turn on - just like on devices of a different type, first of all, you need to check the integrity of the fuses;
• a diode bridge malfunction is a common problem with CRT receivers, you can fix the TV only after making a "ringing", you will need a multimeter from the equipment;
• breakage of the posistor is considered the most serious problem; in order to check, it is necessary to turn off the power 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 malfunction can be easily replaced by visual inspection (on black carbon parts), repair is carried out by replacing the part.

Below is a list of problems encountered by owners of CRT TVs.

1. The Rubin TV buzzes loudly when connected - most likely, the photodetector needs to be replaced.
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, as well as the white balance is disturbed - this is mainly due to a break in the resistor.
2. There is sound, no image - the cause of the problem lies in poor contact of the power connector of the screen board. It is recommended to use a soldering iron to solder the harness into the Horizon TV board.

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

Since the malfunction of the power supply is one of the most common problems of all types of TVs, 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 picture tube, 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 carried out using an incandescent lamp, but before performing the procedure, it is necessary to disconnect Sharp c2002sc, Samsung or another screen from the load (horizontal cascade). The horizontal scan voltage can vary from 110 to 150 V, it depends on the size of the picture tube. 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, it is necessary to unsolder the choke and the fuse through which the JV element consumes power. This scheme is used for sharp screens since 2002sc.

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