In 2014, the production of television receivers with cathode ray tubes ceased. Today you will no longer be able to find CRT TVs with a diagonal of 21 inches or higher. There are still models with a screen diagonal of 14 inches and smaller. The time of CRT TVs has passed, and today mostly all manufacturers produce LED TVs.

A television that is used to display images on the screen cathode ray tube (CRT) is also CRT (Cathode Ray Tube), and is called a CRT or CRT TV. The kinescope contains three cathode guns (red, green, blue), which fire (analogy with guns) a screen covered with phosphor, causing a glow. The work of a CRT TV is aimed at controlling these guns. And the perfection of the picture that we see depends on the quality of the picture tube and the quality of the control circuit. Therefore, when choosing a CRT TV, you need to look at the class of the kinescope and the availability of circuit solutions to improve quality (filters, amplifiers, etc.).

Traditional CRT TVs have been on the market longer than others, so manufacturers have already developed the technology almost to perfection and thanks to this you can choose a reliable, well-displaying, durable TV. If you will use it to watch mainly TV shows and want to save a little money, then you need to choose a CRT TV. It will serve you for more than ten years and such TVs are easier to repair than others.

Appearance of a kinescope television receiver

How to choose a CRT TV based on characteristics

The main disadvantages of CRT TVs are:

• geometric distortion(for modern TVs in the high price range they are almost invisible, especially with flat picture tubes);
• beam convergence problem(for high-priced TVs they are almost invisible);
• big sizes(in depth, different thickness) than LCD and plasma (if there is space for installation, then you can ignore it);
• exposure to magnetic fields(just don’t place speakers or other sources of magnetic fields closer than 1 meter);
• screen size limit(up to 38 inches), for a small room a diagonal of 90 centimeters is quite enough;
• harmful effects on humans due to radiation(thanks to modern technologies, it has been possible to reduce the CRT so much that you can not pay attention to it);

100 Hz scanning in CRT TVs

Another disadvantage of a CRT TV is screen flickering. Due to the introduction of 100 Hz technology, this flicker is almost eliminated. Then the picture will be stable, which will be especially noticeable when reading small letters, and accordingly the eyes will get less tired. With this method, the signal is received from the air with a frequency of 50 Hz, but in a 100 Hz CRT TV, frames are remembered and played back twice in the time it takes to play one frame on a regular TV. But there are also disadvantages to this method. In fast scenes, trails will be noticeable, steps will be visible at the boundaries of transitions, and jitter will be noticeable at the edges of the screen. To eliminate these shortcomings, CRT TVs use various circuit solutions. Using 1-2-1-2 frame alternation eliminates picture jitter. Digital filters, suppressing noise, reduce the loop. Creating intermediate frames inserted between working frames further improves the picture, making transitions more natural. Therefore, do not rush to choose a CRT TV with 100 Hz scanning. Look at the picture when the scene changes quickly (sports, racing) and then make a decision.

CRT TV sound

If you are not going to buy an additional audio system, but want to listen to high-quality sound, then pay attention to the presence of built-in decoding processors Dolby sound in CRT TV.

When buying an expensive crt model, pay attention to the presence of the “picture in picture” and “picture and picture” functions, which allow you to watch two channels at once on one screen. There is also a function for viewing still images from different channels.

Picture tube parameters

When choosing diagonals for CRT TV you need to measure the distance from which you will watch TV and divide by 5. This value will be the diagonal in centimeters (the distance is also in centimeters). With this size, it will be comfortable to watch TV; you won’t see the graininess of the picture and you won’t have to strain your eyesight to see small objects.

When choosing a 3x4 or 16x9 format you need to know what you are going to watch. If you watch a lot of DVDs with widescreen films, then you need to pay attention to the 16x9 format. If you are going to watch only terrestrial television, then choose the 3x4 format.

Better choose a flat kinescope than convex. A flat picture tube has less distortion and a better picture, with less glare from other light sources. But if you watch little TV (dacha, kitchen), then this is not so important. And yet, TVs with flat picture tubes are more expensive.

CRT TVs have good brightness, contrast and color rendition. According to these indicators, they are ahead of many LCD and plasma TVs, and CRT TVs are inferior to them only in the range of functions and appearance. And expensive models with flat picture tubes also have many additional functions, which improve the picture and make operation convenient. And in terms of price, CRT TVs are cheaper than LCD TVs and plasma panels.

Regardless of the TV model (be it LCD, plasma, projection or conventional CRT), it is necessary that it meets your personal requirements for the characteristics of the TV. The most relevant and popular characteristics that are decisive when buying a TV are shown on the pages of our illustrated catalogue. The size of the TV screen, or rather its diagonal, can be indicated in two sizes - centimeters or inches (in most cases it is indicated in the name of the specific model). This parameter is responsible for the most optimal distance from which it is recommended to watch TV. As for liquid crystal (LCD) and plasma TVs (plasma), the diagonal, or rather its size, is also very important. The thing is that when watching TV at close range, the image may appear very grainy. It is also worth paying attention to the screen format and the function of changing the screen format. To watch television programs, it is best to use TVs with a 4:3 aspect ratio. To watch DVDs, it is better to use TVs with a 16:9 format. But most models of modern TVs support both of these formats, but it is better to clarify this point when purchasing.

High-quality sound is far from the last place when choosing a TV. You cannot demand good quality from small TVs due to the small distance between the speakers. Therefore, on TVs with a diagonal of up to 54cm, mono sound may be acceptable. But if we are talking about high-quality television, about watching DVDs, about satellite television, about modern digital cable television, you cannot do without stereo sound.

Controlling a TV is a very important point. A good, well-thought-out menu and control panel will help you use all the necessary functions of the TV without any problems, and you’ll get used to the well-thought-out menu very quickly. The TV remote control should not be too bulky and should be well balanced in the hand. It is very convenient if the buttons are pressed firmly but clearly. And it is desirable that they have protrusions so that you can find the desired button in the dark by touch. It is also desirable that the TV itself have duplication of all remote control controls.

Well, the last thing you definitely need to pay attention to is the TV connectors. In addition to the antenna input, it is desirable that the TV contains connectors such as bells, SACRT, S-video and others. This will allow you to connect different equipment to the TV. Also, HDMI is important for high-definition TVs.

LG CF21D70. When you turn on the TV, after 2-3 seconds it goes into standby mode. The reason is the breakdown of the 2N4148 (150V) diode according to the D408 circuit. Already 3 cases in 3 months.

GOLDSTAR CKT-4905 The TV doesn't turn on. At the output there is 40 volts instead of 115. Moreover, the voltage on the diode is normal, and after the relay 40 the power supply operates without additional overload sounds. The 115 volt diode gets very hot. When checking the secondary circuits, no suspicious parts are found. The capacitor C8075 160V\33MkF turned out to be faulty. Checking the capacitance on the device showed the presence of only 0.23 microfarads instead of 33 microfarads, the leakage was 50 ohms. The defect occurs very often. I replaced the broken TDKS in TV LG: 154-375F, after which I observed a strange effect: service information (program number, menu lines) twitches vertically 2-3 cm, the main image is normal, if you reduce the SCREEN voltage on the TDKS twitching stops, the brightness of the plot also affects. It turned out that the secondary voltage from the TDKS to the personnel power supply was too high - 29v instead of 24v. I put 3 diodes in series in this circuit and that’s it.

TV LG CF-20D30 When you turn on the power button, the LED on the front panel blinks once and nothing more - the power supply has not started, there are no secondary output voltages. The culprit turned out to be the electrolyte in the STRS5707 harness (located between the plates of the STRS radiator, C = 4.7 μF * 50V), which lost capacity up to 1 μF.

Gold Star (LG) 21D16. The guys have done something too clever in this model with stereo sound on an additional board and TDA2009A. In a number of boxes, after six months to a year of operation, a problem appears in the form of a hoarse (farting) and weak sound. The most optimal solution to the problem, without replacing the microcircuit, turned out to be adding 2 - 3 MOhm resistors between the input of the first and second TDA channels and + 12V.

Goldstar CB-28C22X. Narrow horizontal stripe. 2 zener diodes 24V are broken, R304 is charred. After replacing the zener diodes, the band remained, R304 got hot. Replaced the output. k. frame development, TDA8350Q - the resistor has stopped heating, but the stripe is still there. (The necessary diagram is at hand as always). After analyzing the circuit, I found that the personnel ms receives 2 power supplies: for 4 and 8 legs. At pin 4, D702 is broken, FR702 is broken. After replacing the TV started working. (On the Internet, the document for the TDA8350Q can be obtained from the Industrial Electronics website.)

TV Goldstar CF-21E60B. An external sign of a malfunction is a few minutes after switching on - lack of image (dark screen) and sound in the presence of a raster, no response to commands from the remote control (it is controlled from the TV panel), and subsequently - failure of video synchronization and spontaneous entry into the standby mode mode, and after some time the functions are restored, and everything repeats. The malfunction is in the LG8534-13A processor, part of its circuitry - analog adjustments, switching on and off, and the remote control command decoder fail when warming up. Treatment - in secret ¦125, without desoldering, applying a layer of CPT and placing a copper plate on top according to the size of the case, fried with a 65-W solder until the solder on the plate stopped solidifying (8-15 sec). Second successful recovery.

LG CF-21K49 based on the MC994A chassis. The symptom does not turn on or has a narrow vertical stripe on the screen. The capacitor C411 334/200V most likely needs to be replaced.

LG CF-20D30 (Chassis: MC64B). There is no reception on the upper meter sub-band. The malfunction came to light rather unexpectedly. The main one (for which the call was made) was: the network power button (white, expensive 150 rub.) was damaged. After replacing the switch, it turned out that there was no switching voltage for the LV subrange (instead of 12V, only about 5V). The switching voltages are supplied through transistors, a quick check of which showed that everything is OK. Everything was rounded off as if on a tuner (an ordinary eight-legged one). But I have never encountered anything like this before. The doubts turned out to be correct. After soldering small things around the output of the NV tuner, it turned out that transistor Q181 2SA1266 (p-n-p 50V 0.15A) rings like normal at Ohms, but at kOhms it has R(b-e) arr. = 150 kOhm. He then put 12V at the tuner output.

TV LG-CF21D79, oversaturated color image b/w no, as if there is no luminance signal. Replacing the TB1238BN video processor did nothing. The SECAM TA1275AZ chip turned out to be faulty.

TV LG20 on MS-84A chassis. The defect may not be common (I encountered it once), but it seemed interesting to me. Slowly responds to commands, is difficult to configure and does not remember settings. In the service, all the settings were set to zero, but when entering the proper initialization modes and exiting the service, everything repeated itself. Replacing the memory didn't do anything. It turned out that two of the eight resistances in the ceramic assembly showed ~ 2.4 kOhm instead of 4.7 kOhm.

Problem with LG chassis MC-019A. The TV does not exit standby mode if you measure the line power - about 70 volts. First of all, look at the C820 220 MF 160 B, most often one of the terminals of the container is broken, the molding of the terminals is made at a very sharp angle.

LG CF-21D70 (Chassis: MC-64A). When turned on, it goes into standby mode, and then goes out completely. The analysis showed that when mains voltage is applied, the output voltage +V smoothly increases to more than +160 V (norm +125V), and then the internal protection is triggered and the generation of the power supply is disrupted. Analyzing, I discovered a defective electrolyte C824 4.7 μF 50V (leakage, drying out or increase in internal resistance at HF), installed between 4 pins. optocouplers IC801 and 7 pins. STRS5707. What pleases is the timely internal protection, which did not allow the murderous +V=160-180V to run rampant.

TV Gold Star CF21E20 chassis MC-41A No sound. Quite quickly I found that the volume control signal is almost zero, you unsolder the control output of the GS8434-16 control processor (3pin) - it screams at full blast, in AV mode there is also no sound, it would seem that everything is clear, you need to change the percentage - not such a rarity. .. But after the replacement the situation did not change; flashing the FLASH drive to a known good one also did not bring any results. I had to start thinking.... I take out the antenna - after 10 minutes the TV turns off - well, that’s how it is. I leave it with the signal from the air - after the same 10 minutes it turns off - clearly, there is no SOS signal (it is designated here as ID-17pin of the processor) - the level is constantly high. Unfortunately, a stereotype of thinking has worked here - I apply a low signal to this input, but the situation does not change, and in the mode from the video input there is no sound either... In many television processors, the SOS signal is integrated and assessed by level, accordingly, and it is easy to track it - when When the station signal disappears, the level changes sharply. Here the signal is pulsed - SSC pulses are used. Transistor Q06 - ID signal shaper "flowed" the KB transition, there were no pulses at the ID input. In SAMSUNG TVs, when the “sweet couple” failed and the R2M protection broke, the TDKS pierced in the upper part, near the output of the high-voltage wire, a mother-in-law of about 5 mm was formed and a spark shot from it into the core. Here the advice on restoring the TDKS was very helpful - I drill a couple of mm deep into the crack with a large drill and fill it with white auto sealant, after 3 hours you can turn it on. Thus, 2 transformers per week.

On TV LG-21D70X When you turn on or switch programs, information about the settings is not saved. After pressing the power button, the TV switches on to LINESVC mode, from which it goes into normal mode after pressing the TV/AV remote control button. After replacing the 24C02 memory and turning on the TV again switched to LINESVC mode, then after pressing the TV/AV button on the remote control, the TV switched to normal mode with the functions of saving settings restored. No additional actions were required to “firmware” the memory chip.

TVs GoldStar and LG before 2000. Problems with the tuner, does not remember settings, etc. It looks like the tuner has failed. Solder the ground contacts in the tuner.

TV Goldstar CF20A80Y. When turned on, you can hear the scanning operation, but there is no sound or raster. The fault lies in m/s D402 (7809) manufactured by KIA. It stands together with D401 (7812) on the same heat sink, not far from the TDKS.

Gold Star CF-29C44 When turned on, the TV goes into protection. Replace the position number IC7P on the PIP board KRENK 78L08. Almost all malfunctions in these models are related to this KPE.

GoldStar CF-21D60B. No sound. I got a second TV with this kind of damage. The audio control output on the 3rd leg of the LG8434-03C processor is faulty. Our processor costs ~800 rubles. If the client is satisfied with the sound, you can adjust the contrast of this processor. Set the contrast to the optimal value at your discretion. The only inconvenience is adjusting the sound through the menu.

LG CF-20D60. It does not turn on; when measurements are made in the power supply, it starts. It is necessary to replace the 4.7mFx50V capacitance (located in the radiator section 5707).

LG CF-21D70 Spontaneously switches to standby mode. It varies on different channels, on some after 5 minutes, on others after 10 minutes. Try replacing the electrolyte in position C408 with a nominal value of 160V1mF, it shrank to 0 and in addition there was a leak.

LG CT-29K37E. When you turn on the relaxation of the power supply, it enters the operating mode after 5-6 attempts to turn it on and off. It is necessary to replace C808 (100.0x35V) in the power supply, which is assembled on the STR-F6656 chip.

LG CF21D33 - does not turn on. +185v = short circuit to ground - change TDA6107Q (by the way, there was a recently defective batch of these ICs in Promelektronika with the number 3 in the lower right corner)

Quiet beeping is broken D5072. change and get a heartbreaking whistle!!! (What were they fighting for?). It turned out that the Korean saboteurs had smeared the inside of the OS with a new “super-lock glue”. But it’s okay, we are not proud people - we remove the OS, wash the short circuit area. with the purest Russian alcohol, move the coils apart, put in electrical tape - and everything is in place.

GoldStar SF-14A90B within a few seconds of turning on, the screen turned bright white. The KIA7805 (5 V) stabilizer powering the processor turned out to be faulty; during these few seconds it raised the voltage at its output to 7 volts.

Supra CTV1485 MC-41A chassis, also known as Goldstar GF-14/20/21A80 MC-41A/B. In SECAM there is no blue color, in PAL everything is OK. In SECAM, the circuit of the blue B-Y core L504 does not respond to rotation. Do not rush to change the TA8750AN microcircuit; swap circuits L504 and L502 connected through capacitors to pins 35 and 29 of the TA8750AN. In my case, after rearranging the circuits, everything worked; obviously, the soldering of the legs (inside) of the circuit had an effect, after which a slight adjustment of the circuits was required.

LG CF-21F89 chassis MC994A Symptom - turns on for a few seconds then goes into st-by. During switching on, the line transistor manages to heat up. The line coil in the OS is shorted.

LG CF20F30. The fuse is on. The diode bridge and the IC802 STR5707 chip are broken. I soldered the bridge from KD105s, bit off pins 1 and 3 of the microcircuit, turned it on, there are trigger pulses on the 4th leg. I hung the KT872A transistor (k-1n, b-3n, e-2n) on the wires, turned it on and it works. Tr-r placed on a suitable radiator.

LG CF-21D70 chassis MC64A. Spontaneously chaotically goes to the "duty room". Regardless of operating time, heating or cooling. Replacing processors and memory did not give any results. As a result of a long search, the defect was nevertheless identified - the C408 1uFX160V in the Q401 circuit (linear end) had dried out. In these same TVs, B.P. does not start. - drying out of C824 4.7 μfX50v in the optocoupler circuit.

GOLDSTAR assembled on TDA3562A - Dark screen. Reason C -10mF/250V, filter +180V

GOLDSTAR CKT9905 - Pale image, +112V is normal, and the supply voltage of the video amplifiers +180V is too high to +270V - C806 is faulty (47mF/160V)

GOLDSTAR CKT9582 - White raster with reverse beam path - leakage of transistor Q906 (BF421).

LG CF-20K51KE Breakdown of line transistor Q402 D5702 on the body, with burnout. After replacement, the new one flew out within a second. I replaced Q402 with BU2520DX, they are more reliable. A thorough check of the harness did not bring any results. I disconnected one output of the OS horizontal coils and briefly turned on the TV. The screen lit up with a stripe. I turned it on briefly with the OS. The screen lit up with the screen compressed. The transistor remained intact. Replaced OS. The result is positive. I found no defects in the broken OS.

GOLDSTAR 21E60. Doesn't turn on. The line transistor, TDKS and interturn short circuit in the deflection system are broken.

LG CF-14G20R. Weak sensitivity. There is interference and noise in the image. The IF filter of the K6265K radio channel was to blame for this disgrace.

GOLDSTAR 21E40. No high voltage. The power supply works, there is sound. The amplitude of the horizontal scanning trigger pulses based on the pre-output transistor SR is small. On the 37th leg of the video processor the voltage is 0.4 V. Reduced resistor R524 from 3.9 kOhm to 2.4 kOhm. The voltage increased to 0.57 V and its amplitude became sufficient to open the transistor.

ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. (There is no image (may flicker vaguely), the screen is gray!, there is sound. One of the reasons for this defect is the failure of the video signal switch; the chip (GL3820, also known as TEA2014A) is located on the video input board.

ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. Defect - there is no color image in the SECAM system. A fairly common reason is the tuning capacitor SVC1 (located next to the quartz resonator) in the SECAM-PAL transcoder circuit.

ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. The TV does not tune in or the setting is lost. Perhaps it is enough to just desolder and solder the tuner. At least there was a defect.

ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. The TV does not turn on, there is no indication. The standby power supply transformer often fails. TP-8-3, or a similar one, is quite suitable for powering a 12 volt source. However, there was a case when the standby power supply was, it turned out - annular breakage Krenki IC2 (7805) :)

ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. There is no image, the screen is dark green, the “suckers” are visible, there is sound. The reason is the drying out of the air conditioner in the power supply circuit of the video amplifiers (the voltage dropped right up to... 119V, instead of 180-190 set! The screen can be completely dark (the power supply to the video amplifiers in that case was about 160! volts).

ELEKTA CTR-1495EMK, GOLDSTAR CKT-4442B, CKT-9322B. Chassis PC-05X2. The screen is bright white (or gray), brightness, etc. is practically impossible to adjust, the image only skips when you turn on the TV. Most likely this defect is a feature of color blocks with the ABB scheme. The cause of the malfunction is most often the video processor or transistor A1015 on the kinescope board.

GOLDSTAR CF-20E20B When you turn on the TV, there is no screen and sound, but there is high voltage. Fault: stabilizer IC402 (KIA7809)

LG CF-20F30 chassis MS-64A switches off automatically into standby mode from 10 minutes to an hour. The entire board was literally “plowed with elephants and camels”; only the management percentage was left untouched due to its high cost. The reason for turning off the LG8634-16C processor at pin 20, via the ABNORMAL protection bus, is the loss of capacitance of the C408 1uF*160v capacitor in the TMS primary power supply circuit.

Goldstar LG CF-14/20/21A80V Does not exit standby mode. When a switching command is given, the voltage tries to rise and immediately drops to the standby value. Replace SE120N. Sometimes the power supply does not start. The starting circuits should be soldered.

LG CF-21F3. Immediately after switching on it goes into standby mode. No Vsync on processor. Fault-break R15 4.7k

LG, CF-21F39, 2 years. When switching from standby mode to working mode, a burning smell appears and the TV goes back to standby mode. Open the lid and turn it on. There is smoke coming from the left side of the OS. We remove the deflector. On the inside, a breakdown is detected between adjacent windings. At the junction separated by a plastic ridge of the OS housing. The insulation was burned on 3-4 wires on each side. You need to carefully separate them, remove the “coals,” put the wires in a casing and fill them with sealant. The interesting thing is that after 1.5 months the client complains that the same thing happens again. The smell appeared and turned off on its own. I removed the OS and discovered the same breakdown only now on the right. But this is already a topic for thought. As it is written on the TV cover: made in Ukraine from LG components. On the deflector we read: Planzhuan OPC 29-90-54. Made in China. But there is one more point. Rubber wedges that are placed under the OS (of which there are usually 3 pieces and stand at an angle of 120 degrees) here are 4 pieces. Two vertically and two horizontally - exactly under the breakdown site. It seems that the rubber is not conductive, but the heat may not be dissipated well, etc. Or the Chinese are pushing for marriage. Life will show.

LG CF-21D33E, chassis MC-84A similar breakdown of the Pianzhuan QPC 29-90-54 deflection system. Collected in Russia. When trying to replace the OS, there are large dilutions from the top and bottom. The breakdown occurs in two places where the turns from the two coils are closest, located along the horizontal axis. At these points the coils are additionally fixed with brown compound. It is through this that the short circuit strikes. After removing the “coals” and compound from the opposite side, routing the turns, and pouring hot glue, the OS started working. The mixing turned out great.

I confirm this defect. Two TVs in a week. OS Pianzhuan QPC 29-90-54. The TV is assembled in Russia. We couldn't find another OS. The correction is not displayed. Old OSes restored!

GoldStar CF-14A74Y chassis MC41A after a thunderstorm, the STR-S6707 and the TPL721 optocoupler took off. After replacement and when checking the b/p. on an external load of 60W, it worked fine. When you turn on the TV, the 112V channel is set to 85 and 90V, i.e. Voltage jumps from 85 to 90 and back with a frequency of approximately 3-6 seconds. At 85V the screen is compressed horizontally and the screen is white, and at 90V the TV operates normally, but there is a humming noise in the speakers and the line transistor gets hot. The SE110 chip turned out to be faulty (it turned out that the reason was this after connecting an external 150W load to the power supply).

GoldStar CF-21E60B Image distortion, lack of brightness signal, color disturbance. Replacing the TA8750 and the TA8690 video processor and soldering the tuner did nothing. Voltage 12V and 9V is normal. Faulty IC201 LA7222 - video input switch

LG (I don’t remember the model) with a 24C02 memory chip. If, after turning on, you adjust the volume using the buttons on the front panel, then it is adjusted as follows: 0-50-100-mute, if you turn it off in standby mode and turn it on, it fills with white, the protection is triggered. Replacing the memory chip eliminated all problems.

Defect - no frame scan in devices: LG CF-20E60K chassis MC-64A. Resistor R311 2.2 ohm is broken.

Goldstar CF-21D10B There is no image or sound, no noise, the screen is dark. Almost like in secrets No. 487 and No. 949, but - service information is displayed (menu, controls, channel number, etc.) Malfunction: in this case IC401 (KIA 7812) Located on the same heat sink with D402 (7809), not far from line transformer.

LG CF-20K50E chassis MC-84A. It is in the duty room and does not turn on either from the remote control or from the TV panel. It turned out that one 4.7k resistance in the ceramic assembly near the control processor was broken. I hung a similar resistor on the other side of the board: the box worked, but the raster was compressed vertically and shifted to the left. I didn’t go into the service, I changed the memory, the raster became normal.

GoldStar CF-21D60. The raster glows faintly, there is no image, but there is sound. The V-Syng pulse amplitude at pin 2 of the processor is small ~1V. The reason is a broken zener diode ZD01(5V1).

Goldstar CK-20A80. No picture, sound, OSD, video amplifiers are locked. Sometimes he doesn’t even want to turn on from the duty room. The m/s PROM is faulty (**24С04). Solder in a clean one and that’s it.

LG CF-20F60. Received from another workshop with a diagnosis - the processor is faulty. The device behaved in a rather original way: at first it started working, after five minutes it froze and did not want to work anymore during the day. After resting for about twelve hours, he started working again, froze, and everything was repeated all over again. Three resistors in the AR02 assembly turned out to be faulty, two of them were connected to the terminals of the processor’s I2C bus, and the resistor values ​​did not change upward, as is most often the case, but downward. Instead of the required 4.7 kOhm, it became 2:3 kOhm. For reliability, we had to replace the entire assembly with ordinary resistors.

GOLDSTAR CF-25C36X. Defect - no image or sound, weak noise on the screen. Suspicion first fell on the TDA9808 (radio channel), but the cause was IC182 KIA7805 (5 volt power supply to the TDA9808) - instead of 5 volts it gave out 3.

GOLD STAR CF-29C32J Does not turn on (after a thunderstorm). Tr-r Q301 2SB988Y is broken and replaced with 2SB1294. The TV did not turn on, the primary circuit did not start. Broken R811 470k worked after replacement.

LG, MS-64A chassis, power supply on STR-S5707 assembly. The power supply does not start. The leakage in C820 is 220 uF, which is on the 9th leg of the assembly. The capacity showed normal and when dialed with a digital tester it did not reveal itself. The voltage on this leg was 7.2 V (instead of, as it turned out, 7.9 V).

LG modelCF-21K50E. Defect - there is sound, no picture, the screen is dark. Upon opening it, it turned out that there was heat, and there was also voltage on the cathodes. As the accelerating voltage increased, a bright narrow horizontal stripe appeared. The frame microcircuit LA7830 and the 1 ohm resistor for powering this microcircuit turned out to be faulty. The microcircuit flew out due to increased voltage from the power supply (145 volts). The reason is that the electrolytes in the circuit of the power supply microcircuit (STR-S5707) have dried out. After replacing the electrolytes, the power supply began to produce 115 volts.

Goldstar CF-20A80V. The power supply does not start. Before the breakdown, the TV had difficulty starting and turned off on its own. Soldering the ring crack of the TPI lead no longer helped. At 9k STRS6707 supply voltage = 0. (start circuit). The 9th input of the microcircuit turned out to be leaking.

GOLD STAR CF-20D60B. There is no color in PAL, although the screen displays the following message: PAL AUTO SYSTEM. At the output 40 m.s. IC501 TA8690 instead of 4 volts only 2.6. Reason: broken pin 33 (SECAM-ID) m.s. IC01 GS8334-16A. There was no need to change the processor - it was enough to disconnect the defective pin from the circuit.

GOLD STAR CF-20D60B. There is no color in PAL and there is an inscription on the screen: SECAM AUTOSYSTEM. At the output there is 40 m.s. IC501 TA8690 in PAL voltage 0.78 V. TA8690 is faulty.

GOLD STAR CF-20E20B. Another addition to the 509 secret. SECAM is predominantly red. Malfunction of the capacitor built into the circuit L502 E16A (R - Y). The defective one had to be broken out and replaced with an external one at 100 pF with a slight adjustment of the circuit.

GoldStar CF-21D70R spontaneously goes into standby mode at different intervals, and the “ABNORMAL” circuit protection is triggered. A defect has been detected - capacitor C408 1.0 x 160 V has dried out.

LG-CF-20D70K Returning to secret 415. Degradation of the C824 capacitor in the power supply (4.7 * 50 V) initially leads to difficulties turning on the TV, but our people are stubborn. The TV is turned on and off repeatedly. And in the end it will all end with a breakdown of the power mskh STR-S-5707. This malfunction becomes characteristic of LG, along with protection tripping due to a malfunction of the 1.0 * 160V capacitor in the preliminary row cascade.

GoldStar CUT9322 chassis PC-05X2 (with a “flat picture tube” in the form of removable glass). It fills with milk, the image is not visible. Replacement TDA3562A. Still, the effect remained, although the weak image in the negative began to break through. When you touch the 8 pin TDA3562A with the probe, a normal image appears. Conclusion - the constant is coming out through the capacitance C514 0.22mF x 50v. The replacement helped, but not for long. The next time you turned it on, the effect repeated. Searching through containers of different quality yielded nothing. New output - for TDA3562A microcircuits of recent years of production, the input impedance at the Y input (8 pin) has been changed. I connected this input with a 1.5 mOhm resistor. Everything works great. An additional check of the previously soldered TDA3562A confirmed that it was killed precisely at the Y input. A rare coincidence of 2 simple defects leading to pathological consequences, which some masters call a “drum”.

GOLDSTAR(LG) CF-14E20B chassis MC-41B. Lights up red (DR indicator), does not respond to buttons, +B = 43V. The reason is X01 (for some reason it was 3.6MHz). According to the 4 MHz scheme, because it didn’t turn out - I put it at 4.43.

GOLDSTAR (PC04A) 1). Replacement C807 is not included in the operating mode 2). The MC41V chassis cannot be adjusted; the sound cannot be adjusted; the ROM replacement programs cannot be configured. 3). No sound replacement Q06 adjustment L508. 4). There is no setting of the first range setting L508, 507. 5). The frequency of replacing the m-controller is going away. 6). No Y-signal replacement for LA7222. 7). The voltage is reduced by replacing ZD811 by 7.5V.

GOLDSTAR CF-21E20B and other MC-41B. As it warms up it turns itself off and the DR indicator may blink. You can turn it on only after a while. If you do not discharge the filter first and touch the 5th leg of the T802 (there is a ring crack), then you can burn the STRS6707. One device “exploded” simply when removing the board - while putting it on the table (before that the TV was working - but waited until it turned off...). After replacing the STRS6707, you can start it only through a lamp of at least 300W (weaker ones flare up due to the rapidly growing current consumption within a few seconds).

GOLDSTAR CF-21C22X MC-46A. Burnt out when switched on. The DR indicator lights up, but when turned on, it goes out. For a moment, high and all other voltages appear (not reaching the norm), and then immediately fall. When TESTING the horizontal scanning output stage with a reduced +V=+15V - the pulses are without distortion, maybe slightly underestimated, the current is normal. BP without suspicion. I would have suffered for a long time. But I installed another OS and Miracle TV turned on with a narrow chaotic raster. Then the smell of burning was heard. Only a long, thorough inspection of almost ALL the parts of the SR helped. The culprit turned out to be C401 434n\200V. It was under voltage and lost part of the capacity. It was cracked, but it was not noticeable on the board. I think testing would help, not with +V = +15V set too low, but with a gradual increase in +V to the nominal value. But there was no source and it would be necessary to take current limiting measures so as not to burn the test generator itself.

Goldstar channels cannot be configured on the TA8690 video processor. For those that were tuned in, the tune-up went away. The AFT circuit did not work on the TA8690 processor after replacing the processor, it returned to normal

GOLDSTAR CKT9905 Malfunction: after turning on, the TV turns off after 5-10 minutes, while the indicator board goes out. After analysis, suspicion fell on the power on/off relay of the output stage. When the jumper closed the working contacts of the relay, the TV worked normally. After replacing the relay, the TV started working again.

LG CF-20F89. Chassis MC994A. Fault: does not turn on. Power supply based on STRF-6707A (not to be confused with STRS-6707). In principle, none<подводных камней>. The chip itself is to blame. But a thorough testing of its terminals with an ohmmeter did not reveal any differences from the working one. The board was removed from the TV. After replacing the chip, the power supply started up, but after switching from standby to operating mode it took five seconds. went to standby again. Not right away, but I thought of connecting the deflector. It turned out that without her TV does not go out<дежурки>. That's nothing yet. On some Funai units without a connected deflector, the line transistor was knocked out.

LG CF-21S10E There is no frame routing, we change the TDA8351 frame chip. We get an image compressed from below to half the screen, we change the TDA 8842 video processor, the image is normal, but don’t be happy, everything can happen again, and the TDKS 6174Z-8005A is to blame for this disgrace. At times it breaks through.

LG CF14E40 no settings replace -TDA8362-5

Goldstar on TDA4601 When you turn on the TV, the Q801 BU508D immediately fails. When the TV is turned on, there is no startup on the light bulbs, but generation in the TPI can be heard. The power supply on the 9 n TDA4601 is underestimated, on the BU 508 base there are ripples of irregular shape with interruptions (i.e., rectangular pulses of normal shape are absent). Replace the C 801 10X16V. If the Output TP fails, it is MANDATORY to check R 270 Com (with the number of TP through the TPI winding to the 4-leg 4601). There is no start, but sometimes it can turn on, check 12v (power supply 4601, 9-leg - must be 12v to start)

Goldstar on TDA4601 periodically outputs a horizontal transistor (42-cm kinescope), power supply B+ is 140v and is regulated upwards. Check by desoldering the resistance R805 coming from the 3-pin TDA4601 on the B+ regulator (should be from 6k2 to 12k) in this device it has increased to 16k.

Goldstar CBS-6081 The raster glow is very bright, it is not possible to reduce it with the brightness control and Screen on the TDKS, by replacing it, check the BF421 on the kinescope board.

Goldstar CF-20D60B, chassis MC-41B When turned on<цыкает>The power supply on the STR-S6707 does not start. Synchronized with<цыканием>The LED on the front panel of the TV flashes. The ZD811 6.8v zener diode in the KTD2092 base is faulty.

LG - CF-20D73 (MC-84A chassis). The device after a thunderstorm. When the TV was brought to me, there was a processor reset chip (KA7542), a 7805 stabilizer, a soldered SE115 in the power supply, a jumper to power the video amplifier (TDA6107Q), and a line transistor (D5702). I loaded the power supply with a light bulb - it works (the required 115 at the output). By the way, when you turn on another light bulb instead of a fuse, it starts, then the lamp, which instead of a fuse gradually heats up and the power supply is cut off. And without her everything is OK. I soldered the power jumper to the video amplifier, installed a KREN, a horizontal transistor for testing (BU208), cut the horizontal scan through the lamp - it caught fire - short in the horizontal. I disconnected the video amplifier - no short circuit. It turned out to be a breakdown in the power supply of the video amplifier (6 Ohms). The processor (LG-8838-07D CXP86441) also turned out to be dead (breakdown at the Reset 18 Ohm leg). The LED and the diode in series with the LED also burned out. The LED was installed in a suitable size, the diode was KD521. I replaced the processor, video amplifier, installed a D5702 line transistor and a reset chip. The TV started, but instead of a picture there was a screen filled with white (with a pinkish tint) with reverse lines. There is an indication on the screen. Replaced video processor (TDA8842). An image appeared, but filled with white, and with LOCHs. Reduced the accelerating image - the image is normal (in terms of low frequencies). Does not remember settings - memory is faulty (24C04). No channel reception - the tuner is faulty (TV8PSB02D 911A290E). Inside the tuner I found two burnt tracks. Soldered the jumpers. Poor reception appeared only on the 1st band. I replaced the tuner with a 6700VPF016A. The remote control does not work - the IR receiver is faulty. I installed the IR receiver and reset chip from a VCR - they work great. I eliminated a small pink spot on a blue background in the center of the screen by twisting the magnets on the neck of the kinescope. And lightning hit the antenna - the ground track from the tuner to the spark gap with network wires, and another track near the tuner, burned out. In the service I adjusted the AGC and geometry, but did not touch the white balance. To enter the service, press the OK button on the TV and the remote control simultaneously. To switch the menu in the service, you need to press the yellow button on the remote control. Since there was no such thing on my native remote control, I used a Chinese universal remote control.

LG CF-21D70 (Chassis MS-64A) - in use. the mode is turned on. When switched to operating mode, there is a very loud and spectacular “shooting” in the TDKS. Sparks fly in all directions. TDKS type 6174Z-8004B is faulty. Its cost is $18-22. On the schematic diagram of the MS-64A chassis, the TDKS 154-375F type is indicated for a 21" diagonal, the cost of which is $8.5. I installed the 154-375F without any structural and fundamental alterations. The TV worked. The geometry is normal. I configured SCREEN and FOCUS and that's all. But there is a drawback - the screen is quite blue with blue lines. As a result of the horizontal transformer, Q514, Q513 and Q512 (2SA1266Y) in the video amplifier were damaged (instead of 6174Z-8004B in another LG CF-21D70 TV there was 154). -375E. Sellers also offer analogues 154-194D ($10) and HR7906.)

LG CF-21D70 (Chassis MC-64A) - When you press the "Network" button, the power indicator. mode lights up for 2-3 seconds and goes out. The voltages from the power supply when you press the "Network" button have nominal values ​​for 1 second, then they smoothly decrease to 0V within 1-2 seconds (Horizontal scanning does not start while the standby indicator is on, because TV when the button is pressed The “Network” should be turned on in standby mode). The “Network” button is faulty, which supplies power to the TV only while you press it with your hand. The TV owner said that the TV was almost always in dez. mode, i.e. The network button was rarely used.

GOLDSTAR CF-21E20B MS-41 chassis. The problem is that the credits, which usually run at the bottom of the frame, are doubled so that they are impossible to read; the picture itself is of normal quality. I connect the test signal generator, turn on the grid; everything is fine via the video input, but a strong repetition of vertical lines is clearly visible via the RF through the antenna socket; it is clear that the fault lies in the radio channel. In the end, the fault was localized in the K2559 surfactant filter and replaced it with a K2550.

Goldstar CF-20F60. The TV immediately switches on to operating mode, bypassing standby mode. The voltage from the power supply is too high. Optocoupler IC801 is faulty.

Goldstar CF-21C22X chassis MC46A The power supply is based on STRS6707. In operating mode, the TV works without any problems, but when the TV is switched to St-by mode, clicks are heard from the speakers, the frequency and volume of the clicks can change, then after some time the TDKS begins to squeal in time with the sound, that is, it tries to start. The LED glows normally.. I measured the voltage in the power supply according to the line in St-by, it gave out all 80 volts, but it should give out about 40 volts, which is why extraneous sounds appeared in St-by. The capacitor in the power supply is faulty, 10 µF at 100 volts in the secondary circuit, for the control of the optocoupler.

LG KF-21P10 When turned on, the white screen across the entire screen reverses the beam, the TDA6108 and the zener diode on the 5th leg (IK) 7V5 are faulty.

LG CF-21F30K chassis MC 019A The power supply does not start: replacing the line transistor TT2140 with 2SD2499 and TDKS 6174Z-6040C (there are defects in TDKS manufactured on 09-10.2003).

Goldstar CF-14/20/21A80Y. Problem: the buttons on the TV panel do not work properly. The volume is adjusted intermittently. After replacing the memory chip with a clean one, it worked fine. The programmer reads the memory normally, but gives an error when trying to write. When installing a new memory chip with firmware from a faulty chip, the panel buttons stop working again. But old firmware is not required.

Goldstar CF-14/20/21A80Y. Malfunction: in SECAM - the predominance of red color, in PAL the norm. Break out the capacitor built into the L502 circuit and add 100 pF. In my case, I didn’t even need to adjust the contour

GOLDSTAR CF-20E20B (MC-41B chassis). Problem: 30 minutes after turning on the TV, the sound disappears. With the back cover removed, the TV can work normally indefinitely. The GS8434-16A processor recognizes whether there is a telecentre signal by the clock pulses arriving at pin 17 (ID) from pin 21 of the TA8690AN chip. In the absence of this signal, the sound is turned off, and the processor sound control output is set to a level corresponding to the minimum volume. Transistor Q06 (type KT315, this particular transistor was installed during the previous repair) in the circuit for passing these clock pulses was faulty. Anyone who has repaired large quantities of Soviet TVs knows this feature of the KT315.

LG-CF 20F39 Fault: vertical line. Open capacitance 0.364 µF at 400V in the line. Capacitor Manufacturer - WOO YANG

LG-CF14/20/21G20/D70/E60 on MC-64A chassis. Fault: the power supply turns off. At first glance, all the parts are intact; replacing the ic802 microcircuit and the Q810 C3198Y power stabilizer transistor with a zener diode in the base did not give anything. A thorough analysis revealed a capacitor with a low capacity C824 4.7x50V. After replacing the capacitor, the unit starts up. By the way, in earlier releases of these models there was a 220.0x5V capacitor, there were no problems.

LG CT-20T30KE Malfunction: After a while it starts losing 1 channel or all at once. The vertical size may vary. He may pass out on duty. It may become uncontrollable. The sound disappears. Line scanning disappears for a short time, etc. Replacing the memory (you can install a clean one) and quartz did not give any results. Replacing the TDA9381PS\N2\3/0701 processor. When installing processors with different firmware, the TV does not leave standby mode, but changes the firmware in the memory chip as it pleases.

LG CT-20T30KE Malfunction: No PAL color. Replacing quartz 12,000 MHz. Quartz, even new ones, may not meet the tolerance.

Goldstar CF-14/20/21/E20B (MC-41B). Malfunction: in SECAM it turns red, sometimes it works fine. Pin capacitor 26 of the AN5633 transcoder should be checked by replacement.

LG CT-20T30KE. Replacing the TDA9381PS/N2/3/0701(OICTMPH007B) processor with TDA9381PS/N2/3I0792(OICTMPH010A). Everything is okay. Only the raster is slightly shifted vertically down. I had to look for an entrance to the service. 2 OK buttons on the remote control and TV pressed for 10 seconds. did not lead to entering the service, but to turning on the self-test mode, after which the TV went out, but did not enter standby mode

LG, MC-41B chassis. The MV is working fine, but the UHF requires tuning. Setting up the APCG circuit did not give anything. During measurements, it was noticed that TU on the tuner on the UHF range does not change smoothly during tuning, but “jumps”. The defect is in the tuner.

GoldStar (LG) 21D16CF, 20A80Y low PAL saturation, Secam norm, replacement of GS8334-09C microcontroller

Goldstar GF20D60B power supply does not start (STRS 6707), the LED lights up for a second and goes out, chassis MS-1B breakdown of the ZD811 zener diode

LG CT-21Q42KEX chassis MC-019A The power supply does not start, fuse F801 burns out, upon inspection I found a burnt diode bridge DB801 D2SB and capacitor C801 1000p 1kV after replacing the failed parts, the TV started working.

GoldStar CF-21A80Y and other similar models. ATTENTION. When working with a power supply based on the STR-S6707 chip, be sure to discharge the storage capacity 220x400V.

Malfunction: when the network is turned on, the standby indicator begins to blink rapidly. Capacitance C826 220.0x35V in circuit Q805 KTD2092 is faulty.

Problem: brightness is low. When you add brightness to the accelerator with TDKS, the frame: narrow band stops working. The 9V stabilizer turned out to be faulty: power supply to 1 leg of the frame chip.

Problem: The TV may or may not turn on. But if it turned on, when the TV was put into standby mode, the standby mode indicator went out, and the voltage at the outputs of the secondary rectifiers increased by 2-2.5 times. A similar malfunction should be looked for in the stabilization device. In this case, resistor R814 (12k) in the LED circuit of optocoupler IC801 turned out to be faulty.

GoldStar 9322B (PC-05X2 chassis) when turned on, it fills with milk, the brightness and contrast adjustments do not affect, I suspended the 8th leg of the TDA3562A video processor (analogous to KR1024XA4) through 1 MΩ to +, the image began to show slightly. Replacing the microcircuit did not give anything. I rang the transistors on the kinescope board - everything is ok! I decided to replace the Q907 2SA1015 transistor, the tester rings normally. After replacing the TV started working.

LG CF-20F39. Problem: no image. There is a vertical line on the screen. The capacitor in the circuit of the horizontal coils is faulty (I think C412) with a nominal value of 0.36 μF x 400 V - open. You'd never guess it from the outside.

LG CF21D30 chassis MC-64B after replacing the TDKS, burned out R424 10k, broken D401. Malfunction: the TV starts and after a few seconds goes into standby mode. Each subsequent activation from the remote control reduces the operating time. As a result, it turned out to be a broken transistor Q302, which supplies the ABNORMAL pulse to the 20th leg of the processor.

LG-СF21F60K, processor TDA 9381 PS / No. 2 / 3 / 0533 Malfunction: white slanted stripes on a dark screen, light snow appears when the antenna is turned off. According to the owner, the image disappeared when the video camera was connected to the low-frequency input N.Ch. Connecting the 42nd processor leg (external video input) through a 1 Kohm resistance to ground restored the operation of the TV via HF. and according to N.Ch.

GoldStar CF-14A80Y, CF-20A80Y, CF-21A80Y MC-41A chassis. Central processor IC01 GS8334-09A (GS8334-09C) Malfunction: There is no sound in TV mode, there is sound in AV mode. It does not stop while tuning into channels (it skips stations). The leak is Q06 2SC3198.

GOLDSTAR CF20E20B Malfunction: no picture or sound. Upon inspection, I discovered that there was no power supply to the TA8690 video processor. The reason is that the stabilizer IC402 (KIA7809) has failed. After replacing the chip, the TV started working.

GOLDSTAR CF20A80 Malfunction: it turns on in any random program, when you press the program switch button, a menu appears, etc. Replace the 24CO2 memory.

LG CT-15Q91KE Malfunction: no raster. According to the client: It clicked and went out. There is sound and it is adjustable. Channels are switched. When adding accelerating voltage, a gray raster with OX lines appeared. There is no video signal or OSD. When switching channels there is a slight attenuation of the raster. The OX lines are motionless - they do not react to the presence or absence of a signal at the antenna input. Assembled on the TDA9381PS/N2/3I0792 IC. All supply voltages are normal. FB, SSC, etc. input. impulses are normal. The wiring has been checked inside and out, including on the kinescope board. The signal from the RGB outputs reaches the cathodes normally. At the RGB outputs of the IC (pin 51, 52, 53) there is absolute zero. At pin 50 IC (BLKIN - black current input) +7V. I couldn’t find a diagram, the normal voltage is unknown. I tried to ground it. Result: an image appeared, but with OX lines. There are flags on red, but the brightness is normal. The voltage at the cathodes is the same - about 150V. I alternately connect the RGB outputs to ground. After shorting R, an image appears without red color. By selecting the resistor resistance between the output IK (IC TDA6107Q) and ground, I achieved the appearance of an image without OX lines. Denomination - 10 com. The image is bright, except for the flags in red. Conclusion: Loss of emission from the red cathode of the kinescope due to a high-voltage discharge inside the tube. As a consequence, the cathodes of the microtext processor IC are blocked. So, don't forget to check the emission currents of the cathodes.

LG CF-21F30 Malfunction: no startup. The power supply is assembled using STRS5707. Dried C824 4.7x50v

LG-21D33 (MC-84A chassis) Malfunction: after 1-1.5 hours of operation, the TV periodically switches off to standby mode for several minutes. Then it goes into standby mode and does not react to anything. To turn it on again, you need to disconnect it from the network for ~ 0.5 hours. The reset circuit IC03 KA7542 turned out to be faulty.

GOLDSTAR CK21A90 Malfunction: does not turn on (shortly before the breakdown it turned on every other time). The power supply is broken (1.5 mOhm rings) R802 680 com.

LG CT-25Q20RQ Malfunction: does not turn on, the standby indicator does not light up. In the break R830 (like a resistor-fuse, a 0.47 ohm resistor is installed instead of it), is located in the secondary, +12 volts supply goes through it.

Gold Star CF-29C44 MS-51A chassis. Malfunction: When turned on, after 2 seconds it returns to standby mode, a high appears. The device arrived after an unsuccessful repair. They changed the processor and memory in it, and plowed everything up. And all because they didn’t read<Секреты ремонта>. The repair took 15 minutes. Of these, I spent 10 minutes looking for the position number IC7P on the PIP board - KRENK 78L08 (very inconspicuous). When taking measurements at the moment of switching on, 4V appeared at its output instead of 8V. After replacing it, everything worked.

LG CF-21J50K, CT-21Q41KE chassis MC 019A Malfunction: the power supply does not start (clicks). Replacing the line transistor TT2140 with 2SD2499 and TDKS 6174Z-6040C analog HR8656 (if there is a short circuit at all terminals of the line transistor, you will probably have to change the TDKS, there are defects in TDKS manufactured 09-11.2003) in my practice there are three Russian-assembled LG TVs of different brands , but with the same chassis and all the multipliers “died”, but the windings are intact. And the TVs are still under warranty.

LG CT-29K30VE chassis MC 022A Malfunction: there is no image and raster (the screen is black), there is sound, when the accelerating voltage increases, the screen turns greenish with reverse lines, when switching channels the image appears for a second, but without a blue tint and disappears again. Replacing the TDA6107JF video amplifier did not change anything, only after a detailed check of the wiring, the D903 diode on the kinescope board turned out to be leaking in blue, after replacing it with ours from MC-2 (there was no native one) the image appeared.

LG RT-21FA32X Malfunction: the TV does not turn on from standby mode. The C820 200.0x160 turned out to be faulty.

GoldStar CF-20E20 (power supply assembled on STR-S5707). Malfunction: to turn on the TV from a cold start, it was necessary to press the power button 10-15 times. To eliminate the malfunction, it is necessary to replace two containers: C820 and C825, both 220.0x35V.

Goldstar CKT-9902. Malfunction: When turned on, a black arrow 5-10 cm wide is visible at the top of the screen, the direction of the arrow is from left to right. A beautiful, clearly drawn arrow with a crescent-shaped head at the end. 5 minutes after switching on, the arrow disappears. The reason is a voltage boost capacitor in the frame scan of 100 μF, installed near the frame microcircuit.

LG CF-21D30 Malfunction: it goes into standby mode at different intervals. Replace C408 and it is advisable to change C311 and C824.

GoldStar CF20A80Y Malfunction: I press the program switch button on the front panel, everything is displayed, but the channels do not switch. It is necessary to reflash the 24C02 memory chip on the programmer.

LG CF-21D31KE. Chassis MC-019. The sound is accompanied by unpleasant overtones, it seems that either the loudspeakers or the ULF are defective. But a check showed that they were normal. The cause of the malfunction turned out to be the TDA9859 audio processor chip.

LG RT-21FB30M. Malfunction: no image, black screen, OSD present. The IF signal does not pass through, there is no video signal at pin 40 IC01 (CVBSINT) - transistor Q551 (2SA1980) is broken

Goldstar CF-21A80Y. Malfunction: APCG does not work, there is no signal identification. The GS8334-09C processor is faulty. Replaced by GS8434-03B. For compatibility with the original remote control, replace the 4.0 MHz quartz with 3.6 MHz.

Gold Star (MC64A chassis) Malfunction: after switching on, +V jumps to 160V and the internal protection in the STR-S5707 is triggered. Reason - C824.

GoldStar CF21A80Y Malfunction: blurred image (no focus). I checked the voltage from the TDKS-norm, I thought the tube was faulty, just in case I disassembled the kinescope block, the focusing arrester was oxidized (all blue-green), the copper remained, I cleaned the oxidation with a brush, the TV started working, the picture was excellent.

LG CF-20J50K (Chassis MC-019B) - Malfunction: the image is shifted to the right by 10cm, color and synchronization are there. Open circuit C505(222J) of the filter of the 2nd circuit of the AChIF.

LG CF21F60K chassis 019A Malfunction: dark screen, when adding an accelerator, a weak picture with a reverse beam, there is sound, there are graphics. The R456 circuit is faulty, the ABL circuit is broken, after replacement the TV works.

LG CF21F60K chassis 019A TDA9381PS\N2\3 changes to TDA9361PS\N2\4I0793 (from LG CT-21Q42KEX).

LG RT-29FA55RB MC049A Malfunction: the TV does not exit standby mode, the protection is triggered, the TDA6109J needs to be replaced. I tried to replace it with a TDA6108J: the TV turned on but after 15 minutes it went into standby mode, it was necessary to replace it with a TDA6109J.

GOLD STAR CF-29C36X. MC-51B chassis. Malfunction: the TV does not turn on from standby mode; when turned on, the DR indication LED lights up green, after a second it turns red, and so on. If you remove Q803 (C3228), the TV turns on, the line starts, but the screen is dark. IC351 TDA8350Q is faulty. After replacement, there is a “crease” in the image vertically due to an increase in the resistance of the breaking resistor FR359 (10 Ohm - 0.5 W) for +45 V power supply. Replaced, as well as FR351 (2.2 Ohm) for +20 V power supply.

LG CF-21D30 chassis MC-64B. (The power supply is assembled on the STR-S5707) Malfunction: when turned on, the red LED on the front panel begins to blink constantly with a frequency of approximately 2 Hz, and relay clicks are heard in time with the blinking. The TV does not respond to either the remote control or the control buttons on the front panel. I left it turned on in this state. After about 10 minutes a wisp of smoke appeared. The problem was found on its own. A small capacitor C813 470pFx1000 V was smoking in the secondary circuit of the power supply (it shunts the +V rectifier diode). After replacing a capacitor with similar parameters, the operation of the device was restored.

LG-CF20F39 (chassis-MC994A) Malfunction: the power supply does not start, the line transistor 2SD2449 is broken. In the harness I noticed “familiar” capacitors from the WOOYANG company. One of them is 0.334x400 in a cliff. Although TVs with such a malfunction have a vertical thread, the transistor does not knock out, so I also replaced the 1600 volt capacitor (also from WOO YANG).

GOLDSTAR CF-20D70B Malfunction: no color in the SECAM system. As a result of the search, a faulty Q512 2SC3198Y was found. I increased the voltage at pin 13 of the processor to 2 volts.

Goldstar CKT-9742. Processor SAA1293-02. Malfunction: all signs of MDA2062 memory failure (incorrect operation of the buttons on the front panel, etc.). Login to the service using the RS-4 remote control, sort through the optional bytes with the SERV button, and save changes automatically. I set the option bytes similarly to SAA1293-03 (as in 4USTST).

GoldStar CKT9745 (PC-91A) Malfunction: does not turn on, the relay clicks. R805 -820k in the power supply unit is faulty.

GOLDSTAR MS-41A chassis. The LG8634-02A microprocessor will be replaced with a GS8334-03B. The only difference is the RGB wiring for sending signals to the video processor.

GoldStar chassis MC-51A. Fault: a second after switching on it turns off in STBY. The famous 1C7P (7808) has nothing to do with it, just like the PIP board itself. After several unsuccessful hours to revive the TV, IC806 (KIA7809) was discovered located next to the power supply, which produced 4 volts at the output. After replacing it with KREN8A, everything worked.

Goldstar CKT-4822. Problem: no image. Is there sound. The screen lights up only if you add an accelerator. Everything seems to come to the TDA3561A video processor (they changed it before me, but did not achieve any results). The problem turned out to be his diet. The device showed the required 12V on the first hoof. It is necessary to replace the electrolytic capacitor 330.0x25V, which is located in front of the 12V KRENK after the diode (power comes from the line trans). It should be noted that after the above replacement the TV started working, but poorly. We had to replace several more electrolytes to power different cascades.

LG CF 20S10E. Fault: the TV does not turn on in operating mode. Composition: ICO LG 20S10E IC 501, TDA 8842 S1. The problem is in the resistor assembly AR02 4.7k 9n in an open circuit: 0 ohm. Replacing the AR02 4.7k assembly restored the TV's operation. Also 1204 1184. To the above, we can add: failure of the TV to switch on to operating mode occurs when AR02 fails and when AR01 fails. But if AR01 fails, the memory is always intact! And when AR02 exits, a memory failure is possible, even a horizontal scan transistor may fail.

GoldStar CF-20D60B, Malfunction: the mains fuse is on, STRS6707 in the power supply has failed. Be sure to check and, if necessary, replace C825, C826. Otherwise, the STRS6707 may fail again.

LG-21Q42KEX chassis MC-019. Malfunction: there is no horizontal and frame synchronization, there is sound. Replaced processor TDA9361PS/N2/4I0793 (OICTMH006C).

GOLD STAR CF-14A80B chassis MC-41B. Malfunction: reduction in the number of channels received by the TV. The VH range (+12V) on the tuner is constantly turned on due to a leak in the Zener diode Z003 (7V5) in the Q11 DTA114 key control circuit.

LG CF20E20 Malfunction: Unpredictably switches off to standby mode (after ~ 3...30 min.). Reason: loss of capacitance C408 1.0mkF 160V in the filter of the horizontal scanning pre-output stage. On the faulty condenser the cartoon showed 42V, after replacing it 33V. Oddly enough, the temperature of the output transistor was normal.

LG CF-21D30. Malfunction: the TV does not respond to channel switching buttons, confuses commands from the remote control, and periodically goes into standby mode. The m/s PROM 24С04 is faulty. You can replace it with a new one that is not stitched.

LG PT-53A82T Malfunction: the convergence has “scattered,” specifically, the red beam on the cross in the menu option does not converge. The STK392-120 datasheet is faulty, there are two of them - for the blue and red projector. After the replacement everything is fine. Attention - a real STK costs about $35.

GOLDSTAR CKT-2190, SHIVAKI STV-206M4, assembled on the PC-04A chassis Malfunction: when turned on, there is no sound and color in the image, skips programs in automatic tuning, and with warming up the defect may disappear. After diagnostics, it turned out that the electrolyte C409 0.22mk on the 5th leg of the TDA1940 according to the circuit had dried out.

Goldstar SKT-2190. Malfunction: brightness increased, darkening on the left side of the screen with a change in brightness. Replace C431 2.2x250v (power supply for video amplifiers).

LG CF-20F39 chassis MC994A. Malfunction: came in for repair with an expired TDKS, the resistor in the ABL circuit also burned out. Someone has already changed TDKS. After replacing the TDKS and R 33k, the TV started up. When measuring the supply voltage. lines, it was detected that it gradually increased to 150-160V; the protection did not work. Troubleshooting the stabilization circuit in the power supply revealed a dead optocoupler IC801. Replaced with PC120, everything went as it should. The lower case tr-r in this chassis without a radiator, I consider this a flaw of LG - fix it! I won’t repeat myself about WOOYANG capacitors.

Goldstar CFZ-9822. Malfunction: TDKS 154-177E has failed. This TDKS has a Booster output. Such TDKS is in short supply. It is possible to change it to the common 154-177J. Minimum alterations: Wind 5 turns of insulated mounting wire onto the TDKS core, solder one end to pin 3 of the TDKS (92 V from the power supply), the other end to + C705 100 x 63 V (booster). Determine the winding direction experimentally; if you mix it up, nothing catastrophic will happen, just all the secondary voltages of the TDKS will be underestimated. Cut off the tracks from pins 5 and 6 of the TDKS and swap them (these are 12 and 24 V voltages). You can not cut the tracks, but raise the resistors connected to them and solder them crosswise. Cut the track from pin 4 of the TDKS and connect it to ground. Cut off the track from pin 7 of the TDKS (do not connect it anywhere, since this pin at 154-177J is 40 volts) All other pins are the same. The number of turns of the wound additional winding changes all secondary voltages of the TDKS in direct proportion. (more turns - more voltage.) If in your case the voltages are too high (or too low), adjust the number of turns to suit your option. I selected the number of turns and controlled the output voltages to power the video amplifiers (180 V), and only then checked the rest.

LG CF-20D70 chassis MC-64A Malfunction: line scanning does not start. D408 1N4148 turned out to be faulty, although when checking there is no leakage, even with a digital device.

GoldStar SF-21E20B. Malfunction: 30 - 40 minutes after switching on, it goes into standby mode, which is accompanied by a blinking LED on the front panel. Subsequent inclusion in the operating mode was possible only after “cooling down”, and for a period of no more than 30 - 40 minutes. The reason is poor soldering of the terminals of the pulse transformer of the power supply. After soldering all the pins, normal operation of the TV was restored. The defect was discovered only after a thorough examination of the printed circuit board through a magnifying glass.

Goldstar CF-20D70B. Chassis MC-41B. Malfunction: after several minutes of operation, a group of broken lines appeared in the upper part of the raster, and when working from the video input, such a defect was not observed. The reason turned out to be the switch chip IC201 (LA7222) - it was wasting the video signal.

Goldstar CKT-9902. Chassis PC-04A. Malfunction: when switching from standby mode to working mode, the indicator LED goes out, but the device does not turn on. The reason turned out to be a broken diode D401. It is located in the power supply circuit of the horizontal scanning pre-output stage. Replaced with diode D226D.

GoldStar CF-21A80Y, also known as CF-20E20B chassis MC-41A. Processor GC8334-09B memory 24C02. Malfunction: when turned on by the network button, it spontaneously switched to operating mode on channel 89 or 91. The buttons on the front of the TV turned on everything except what they were supposed to display. After replacing it with clean memory and tuning to channels, everything was restored.

LG chassis MC-64A. Malfunction: after switching on, after a while a clapping sound appears and, in time with this sound, a raster begins to appear, which gradually expands horizontally to its full size. Diode D408 (1N4148) is leaking. It stands next to the famous capacitor C408 in the ABNORMAL circuit.

GOLDSTAR-CF20A80 (MC-41 chassis). Problem: low sound with distortion. Audio conversion from multistandard to IF = 6 MHz has been applied. The 6.0 MHz SFE filter on pin 49 of the TA8690AN has failed.

LG CF-20F30 Malfunction: does not start. Turn off the horizontal scan and connect the control light. The power supply started up, the control light came on and all voltage appeared. However, the fault could not be identified in the scan. I had to go back to the power supply. It turned out that the capacitance of C824 4.7x50V was lost to 2.8 µF

LG Model CF-20F80 Chassis MC-84A Malfunction: received for repair with a malfunction no image, sound is normal, although service information is displayed normally. At high magnification on the SCREEN line, a very weak inverse image appeared on the screen along with reverse lines. The cause of this malfunction turned out to be the ZD741 8.2V zener diode on the ABL line. After replacing it, the picture appeared and the TV worked fine.

LG RT-21FA72X chassis MC-019. The device after a thunderstorm. Malfunction: when turned on, an image appears for a second and immediately turns off into standby mode. The processor TDA9381PS/N2/4/0703 (OICTMPH006B) is to blame. Successfully replaced by TDA9381PS/N2/4I0793 (OICTMPH006C).

LG CF-20K50E chassis MC-019. Malfunction: does not turn on from standby mode. On leg 4 of IC803 (STRF6654) 13 volts instead of 18.9 volts. C801 is faulty (100.0x35V).

Goldstar CF-21E60X chassis MC-64A. Malfunction: switches off to standby mode at different intervals. Reason: breakdown of D401 (1N4148) and leakage of transistor Q302 (2SC3198). After the replacement, the TV stopped turning off.

LG RT-21FB30M chassis MS-019A. Problem: TV after a thunderstorm. When turned on, a raster appears, but there is no image or sound. The menu turns on, all control buttons work. The setting turns on, but doesn't find anything. The culprit turned out to be processor IC01 TDA9381PS/N2/3I0792 (OICTMPH010A). After the replacement everything worked.

Goldstar CF-21C22X MS-46A chassis. The TV doesn't turn on. When you try to turn it on, the indicator goes out, but there is no voltage at the output of the power supply. A broken transistor Q812 (KTC1026) was found in the power supply. There are no changes after the replacement. Next, transistor Q2 (KRC102M) was found to be leaking (replaced with DTC114ES) and IC807 (KIA7812P) was broken. After this, the TV began to turn on, but when turned off, the raster and sound disappeared, and the scans continued to work. Transistor Q105 (KRC102M) was found to be leaking (replaced with DTC114ES). The device worked fine.

GoldStar CF-20A80Y chassis MC-41A Malfunction: during a cold start, the TV turns on poorly (every 10 times), the hum of the pulse transformer is heard, as well as an unpleasant hum in the speakers, the output voltages are too low. There were dried capacitors in the power supply C815, C820 10.0x100V, C826 220.0x35V

Goldstar CF-20A80Y chassis MC-41A Malfunction: when turning off the TV from the outlet or using the power button, the settings were reset to factory settings (brightness, contrast, turning the TV on and off) IC02 24c02P turned out to be faulty

LG RE-29FA33X Malfunction: the image periodically disappears and after 5 seconds. goes into defense. A staffing loss has been detected. The reason is the cold soldering of the TDKS legs - all except those installed on rivets. The legs of the TDKS are covered with a plastic frame for the monoboard.

LG CF-20E20 Malfunction: the TV does not turn on, the LED does not light. Found, K.Z. powerful transistor in STR S 5707, 120 ohm leakage in the 4N35GV optocoupler between the 4th and 5th legs. S820 220 μF 35V and S825 220 μF 35V changed their capacitances. I replaced everything, the TV does not turn on, the LED does not light up. I measured the C - meter C824 4.7 μF at 50V - the norm, but the ESR is more than 30 ohms, replaced the C824 and the TV started working.

LG CF-21J50K chassis MS-019A Malfunction: the TV lights up, there is no reception on any channel, there is no sound. The TV works at low frequency. In the service mode of the TV, as regards the selector and IF, it corresponds to the tabular data. I checked the data bus and synchronization bus with an oscilloscope; there are rectangular pulses filled with a higher frequency. The channel selector voltage is correct. I disconnected the IF selector, fed the IF from another TV, the image appeared. Using Laspi-TT-03, it is impossible to check the IF, the signal level is low. I replaced the selector and the TV started working.

LG CF20E20 Malfunction: the TV works, but on different bands with different periods of time, it goes into standby mode. By pressing the program switch button on the remote control, the TV works again for 20 sometimes 30 minutes. On the IC01 processor on the 20th leg of AVNORMAL, the voltage was changed and the power supply was switched to standby mode. C408 1.0x160 volts, in my case: the c-meter showed normal capacity, and the ESR meter was more than 30 ohms.

LG 20E20 Chassis MC-64A. Problem: the power supply on the STR-S5707 does not turn on. The reason is the loss of capacitance of the capacitor C824, which is located on the 7th leg of the microcircuit. Apparently this defect is due to the not very good location of its installation - between the fins of the radiator.

Nowadays, even a child knows what a TV is and uses it constantly. Technologies are constantly improving, CRT TVs are becoming a thing of the past. They are being replaced by liquid crystal monitors, as well as LED technologies.

Nevertheless, we will talk specifically about CRT TVs, because many continue to use them for certain reasons. They are also called CRTs.

Device

If you get very close to a CRT TV, you will find that the picture on its screen consists of miniature dots. They flicker, burn brighter or dim. If you move further away, what is happening on the screen is perceived as a moving picture. This is explained by the ability of the human brain to collect everything into a single whole.

CRT TV screens are shaped like a pear. In the place of the “handle” there is a so-called electron gun, which directs electron streams to the screen. The surface of the screen is filled with phosphor dots. This is a substance that glows when an electric beam hits it. These tiny dots make up the whole picture on the screen of CRT televisions.

Where does color come from?

The screen of a color CRT television is even more complex. On it, phosphors have different properties and glow in green, blue and red. All other colors are obtained by mixing these three.

An electron beam rapidly shoots into the screen and impacts the phosphor points 25 times in an instant. As a result, the human eye sees a moving image. Electric rays “run” across all the lines on the screen in the shortest moments.

Specifications

CRT TVs differ in technical parameters:

• Screen size. The larger it is, the larger the TV itself. This means that the largest TV will not fit in all rooms. If the dimensions of the room are modest, you need to choose small equipment too. The smallest TV has a diagonal of 10 inches. Models with diagonals from 14-15 inches, as well as 20-25, are popular. The largest are 29- and 34-inch. When choosing a screen, you should determine in advance where the device will be placed in the room. A mandatory requirement is the presence of space between the housing and the wall. Otherwise, the equipment will quickly fail.
• Screen format. Typically 4:3 is used. 16:9 widescreen is preferred for watching movies. TVs also have automatic format adjustment.
• The scan, or rather its frequency, indicates the quality of the image. In previous models it was 50 Hz, so the viewer had the feeling that the picture was constantly flickering. Later the frequency was increased to 100-120 Hz.
• Speakers. In small models they are usually built-in, while large versions have stereo speakers.
• Connectors for connecting devices. Models that are produced these days are already equipped not only with connectors for connecting an antenna. As a rule, they have audio and video outputs to which you can connect video and DVD equipment.

Advantages and disadvantages

The advantages of CRT TVs are:

• affordable price;
• variety of models to choose from;
• excellent picture quality;
• realistic color;
• long service life.

The disadvantages of the technology include:

• large dimensions;
• negative effects on the organs of vision during prolonged viewing.

Image problems

Let's look at the most common faults of CRT TVs:

• Cloudy image on the screen. This happens due to a broken kinescope. During repairs, the repairman can perform additional winding on the transformer, but in the future the screen will need to be changed. If a bright glow with thin horizontal streaks appears on the screen, such a kinescope cannot be restored.
• The screen went dark. This occurs when the filament breaks or a shorted cathode is detected. In case of such a malfunction, the technician checks for the presence of a circuit between the contacts. If there is no circuit, the screen cannot be repaired. In another case, the technician solders the contacts and fixes the breakdown.
• Image offset. In this case, the penetration of rays onto the phosphor is disrupted. You can try tapping the edges with a rubber object, but most often you have to change the kinescope.

Typical defects of some models

There are also typical defects in some models. For example, in Samsung CRT TVs the power supply often burns out. The technician changes the mains fuses. It is also possible that the image may be damaged due to a faulty thermistor; it must be replaced with a new one.

If the TV suddenly starts smoking, you need to turn it off and immediately call a technician. Usually the cause of the breakdown is swollen capacitors, which are replaced with serviceable ones.

Erisson TVs may not transition from standby mode to operating mode over time. This is explained by the fact that the device activates protection against burn-through of the kinescope if there is a breakdown in the frame scanning units. Replacing a faulty transistor with a working one can help.

LG CRT TV is susceptible to another breakdown. Over time, it may not turn on. The technician will inspect and check:

• are the capacitors working?
• are there any microcracks in the board and power circuit;
• whether contact detachment has occurred.

When any breakdowns are detected, the technician fixes them, and the equipment makes its owner happy with its working condition.

Of course, the repair of CRT TVs should be entrusted to professionals. In this case, you can be confident in the quality of the service, and the TV will last for many years.