DIY samsung led TV repair at the top of the strip

In detail: do-it-yourself repair of samsung led TVs at the top is a strip from a real master for the site my.housecope.com.

Samsung has long been one of the most popular brands sold and serviced in Russia.
The choice of buyers is justified by the favorable price-quality ratio of the equipment, and the popularity among repairmen is due to many factors that determine the simplicity and ease of repair and maintenance.

Despite the variety of models, Samsung TVs for technicians and service engineers remain uncomplicated and predictable in repair, and the manufacturer's timely technical support with components, modules, documentation and software greatly facilitates and simplifies diagnostics and repairs.

Since the beginning of the nineties of the last century, the craftsmen have accumulated rich experience in repairing Samsung TVs, which was discussed and preserved on the Internet in numerous conferences and blogs of repairmen.
Typical defects of some models sometimes caused controversy and deserve special attention in considering the causes of malfunctions and methods of their elimination.

In this series of articles, it is planned to consider the most common malfunctions of Samsung CRT TVs from 2000 and the most popular LCD TV models in the repair practice.

There is no need to consider the problem of electrolytic capacitors in the rectifier filters of power supply modules, since this is a massive trend characteristic of the first generation of LCD TVs. It should be noted that in LED TVs, the problem with electrolytic capacitors is less common. Perhaps this is due to the lower consumption of LED backlight power converters.

Video (click to play).

Operation of some first generation Samsung LCD TV models with defective power filter capacitors may cause software failure. At first, the settings for the channels may disappear, sometimes specific distortions appear in the “Cinema” mode, the screen backlight adjustment may not work correctly.
Often there is a complete failure in the software and the TV is no longer included in the operating mode.
In such cases, after repairing the power module, it is necessary to replace the contents of the EEPROM memory.

One of the most popular power supplies in repair is described separately in the article Typical faults BN44-00192A. In addition to defects caused by a malfunction of electrolytic capacitors, we note two more typical malfunctions of this module. Ring cracks in the soldering of the terminals of the switch-on transistor from standby mode, as well as breakdown of the sealant with subsequent short circuit and damage to the 2200pF capacitor and breakage of the 0.22 Ohm resistor in the power supply circuit of the key transistors of the converter.

Noise in the image in the form of curved oblique stripes associated with poor filtering of the tuner's power supply is eliminated by replacing the 100uF 16V capacitor on the main board. In this case, there is no need to change the capacitor in the tuner. Sometimes the masters do the opposite, due to insufficient competence, then such a replacement will help for a short while.

Another popular typical malfunction of some Samsung LCD models is the use of the AS-15 gamma correction chip in the T-CON board. AS19. The defect is associated with distortion of color transitions. The image becomes lighter and in places looks like a negative.

The latest LCD models, SMART-TV in particular, have problems with BGA soldering technology for highly integrated chips.In such cases, malfunctions may occur, usually manifested with warming up, which are caused by a violation of the contact of the chip pins with the corresponding pads on the board.

The malfunction of the LCD matrices is perhaps a separate topic for discussion, but it makes sense to briefly consider some of the external manifestations of its defects.
In most cases, these are straight vertical stripes in certain areas of the screen or throughout its entire area. Stripes can be different, both colored and black and white of different thickness.
Sometimes the nature of the stripes changes with external mechanical stress. Freeze-frame images may appear.
Such matrix defects are associated with broken contacts in the connections of the loops, which can sometimes be restored with warming up.
Repair of the matrix in such cases is associated with its disassembly and restoration of contacts in loops or duplication of connections with external conductors - a complicated process, not recommended by manufacturers and may not always be a successful and reliable solution to the problem.
Due to the fact that the price of the matrix is ​​quite high, accounting for more than half of the cost of a TV, in most cases, owners of post-warranty TVs refuse to replace the matrix due to the economic inexpediency of repair.

In many models of LED TVs of the 5 series, panels (matrices) with backlight LEDs of sufficiently low quality are installed, or the current in the LEDs is incorrectly calculated. This currently popular typical defect can manifest itself already in the first year of operation. In this case, there is simply no picture.
In authorized service centers, on the recommendation of the manufacturer, they change the LED rulers and limit the current in the LED drivers so that the TVs work out at least the warranty period. And in post-warranty cases, this problem is solved by the craftsmen in different ways, depending on their qualifications and contractual conditions with the owner.
Some explanations and recommendations can be found in the article in our article Repair of Samsung, LG LED-backlights.

Of the most common malfunctions of Samsung CRT TVs, there are several associated with the low reliability of CRTs and their deflecting systems (OS).

The consequence of shorting the filament with the cathode of the kinescope (usually green) is eliminated by isolating the filament from the mass and organizing its separate power supply (2-3 turns per TDKS core). In this case, do not forget to use the standard filament current calibration resistor.

In kinescopes with a flat screen, diagonals of 20 inches or more, a short circuit between the accelerating electrode and the modulator (G2 and G1) often occurs, which is accompanied by the absence of an image.
Fortunately, such short-circuits, in most cases, can be easily eliminated by the usual old-fashioned methods popular among repairmen.

It is more difficult with the closure in the lowercase deflecting coils of the CRT. In this case, the line transistor short-circuits, usually immediately upon switching on. In some cases, you can see smoke from under the throat of the OS, feel the characteristic smell, the transistor (HOT) overheats at this time.

A lot of trouble in many models of Samsung CRT-TVs of different diagonals is delivered by the elements of the IOC capacitive divider of the horizontal sync pulse formation circuit. In such cases, the limiting resistor often burns out to charcoal, sometimes damaging the board section along with the conductive tracks.

In cases with “floating” defects, when it is not possible to detect poor contact in the soldering of the element leads, it is necessary to remember the specificity of the metallization of the holes in the power circuits of the horizontal scan, which is characteristic of Samsung CRT TVs.
The contact of the metal sleeve with the copper pad of the board is often painted over, sometimes it is faster to detect sparking in this place than to see an annular crack with a magnifying glass.
Most often, such a breakdown of contact occurs at the place of soldering of the contact pad with metallization of the collector connection of the line transistor.

Typical malfunctions of some common models made on standard chassis can be considered separately.
Pages will be added as the material is prepared.
Typical defects and repair of Samsung chassis KS1A - From the practice of repairing Samsung KS1A TVs.
Typical defects and repair of Samsung chassis KS2A - From the practice of repairing Samsung KS2A TVs

According to the functional composition of CRT (with a kinescope) and LCD (LCD) TVs, separate sections have been created on the site, where modules and elements for well-known and popular models for repair are indicated in the tables:
Composition of Samsung CRT TVs - Functional composition of Samsung CRT TVs.
Composition of Samsung LCD TVs - Functional composition of Samsung LCD TVs.

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Some useful recommendations for owners who decide to buy a new TV due to the unrepairability of the old one can be found on the page: how to choose a TV when buying.

Comments and suggestions are welcome!

It is no secret that a breakdown of a television receiver can ruin the mood of any owner. The question arises, where to look for a good master, do you need to take the device to a service center? You need to spend your time on this, and what is important - money. But, before calling the master, if you have basic knowledge of electrical engineering and know how to hold a screwdriver and a soldering iron in your hands, then repairing the TV with your own hands in some cases is still possible.

Modern LCD TVs have become more compact and easier to repair. Of course, there are breakdowns that are difficult to detect without special diagnostic equipment. But most often there are malfunctions that can be detected even visually, for example, swollen capacitors... With such a breakdown, it is enough to evaporate them and replace them with new ones with the same parameters.

All TV sets are the same in their structure and consist of a power supply unit (PSU), a motherboard and an LCD backlight module (lamps are used) or LED (LEDs are used). It is not worth repairing the motherboard on your own, but the power supply unit and screen backlight lamps are quite possible.

As already mentioned, the design and principle of operation of LED and LCD TVs, regardless of the manufacturer, are the same. Of course, there are some differences, but they do not play a significant role in the diagnosis of faults. Often, in the event of a problem with the power supply, the LCD TV does not turn on at all, while there is no indication, or it turns on for a while and turns off spontaneously. Using an example, the repair of a DAEWOO LCD power supply unit (can be applied to plasma) is considered, which is not much different from repairing an LG TV, as well as Toshiba, Sonya, Rubin, Horizon and similar models.

  1. First of all, before you repair the TV, you need to remove the back panel of the device with a screwdriver by unscrewing the screws. On some models, the rear wall may be latches installedwhich must be handled with care so as not to break them.
  2. After removing the cover, you will see the power supply unit, consisting of several modules on the left, and the motherboard on the right.
  3. Image - DIY samsung led TV repair at the top of the strip
  4. On the power supply board you can see 3 transformers: the bottom one is the mains rectifier choke, the top one on the left (large) feeds the inverter, and on the right is the standby power supply transformer. You need to start checking with it, since it turns on the standby mode of the TV receiver.
  5. Duty transformer when the device is connected to the network, it should give out a voltage of 5 V. In order to correctly find the wire on which you need to measure the voltage, you can use the diagram, or you can see the markings on the case. In this case, opposite the required contact is written - 5 V.
    Image - DIY samsung led TV repair at the top of the strip

Measurement is taken first open circuitby connecting one probe to the found contact, and the other to the cathode of the diode on the radiator. In this case, there is no break.
Image - DIY samsung led TV repair at the top of the strip