Such a manifestation of the defect is due to the fact that in the event of a malfunction of the frame scan units in the TV, the protection against the kinescope burn-through is activated.
If you leave a TV with such a defect on for a long time, then later in the place where there was a horizontal strip there will be a section with a lower luminous efficacy (burnt-out phosphor ) - the picture tube will be damaged. To avoid this, modern TVs have built-in protection against kinescope burn-through and the TV simply does not switch from standby (sleep) mode to working mode.
On the CRT screen, there is a bright horizontal line in the middle of the screen. In this case, the protection against burn-through of the kinescope does not work, since the electric circuits of the frame scan are working, but the faulty elements still partially fulfill their function and the protection system does not “see” that a malfunction has occurred. Therefore, a bright horizontal stripe appears on the screen.
If there is a horizontal bar on the screen, then try to turn off the faulty TV as soon as possible in order to prevent damage to the kinescope.
It was with such a malfunction that the TV got on the repair table. Erisson (model 1401 , manufacturer Telebalt LLC, Kaliningrad). The TV did not switch from standby to working 2SB764 E –TO ... The resistance between the emitter and collector leads was zero. This is what caused the protection against burn-through of the kinescope to operate.
On the circuit board, the 2SB764 transistor is designated under the serial number Q406 LA78040N
After replacing the 2SB764 transistor with a new one, the TV began to turn on, but a bright strip formed on the screen in the middle of the TV picture, and the image at the top of the screen was nonlinearly elongated. Teleradiomechanics call such a defect “bloat wraps up ... The photo shows a twist formed after replacing the 2SB764 transistor.
In addition to the resulting vertical twist, the new 2SB764 transistor got very hot during TV operation - there was still some faulty part in the circuit, leading to overheating of the replaced transistor. When turned on, the TV did not turn on for a long time, and the image first appeared in a narrow strip in the middle and then slowly expanded to full screen.
After a short search, it turned out that in a switching power supply, an electrolytic capacitor (47 microfarads. 50 V.) has a small capacity, which amounted to 19 microfarad.C933
If you encounter a similar malfunction, be sure to check this capacitor.
After replacing the capacitor in the power supply, the image began to appear faster, but despite this, the image, when turned on, unfolded as if from a pillow. Transistor 2SB764 still very hot
If you wander on the Internet on the electronics repair forums, you can find recommendations for replacing the 2SB764 transistor with a more powerful transistor 2SB772 Erisson , in order to exclude the breakdown of the 2SB764 transistor and the repeated failure of the TV - relapse .
In practice, it is not always possible to find a 2SB772 transistor. In this case, you can use a domestic transistor KT814 P-N-P
After installing the domestic KT814 instead of the imported 2SB764, the TV began to work properly - the “twist” disappeared, and the excessive heating of the transistor stopped.
When repairing a TV Erisson 1401 with the described malfunction, first of all, check the 2SB764 transistor (Q406 2SB985
A similar malfunction was observed in Erisson 2102 ... The already known transistor 2SB764 turned out to be faulty.
Darkening was observed on the circuit board around the 2SB764 transistor - evidence of excessive heating of the transistor. Due to overheating, the 2SB764 fails. Burnout of this transistor in TVs Erisson Is an explicit “bug ”. The Erisson 2102 was restored by replacing the faulty 2SB764 with an analogue 2SB985.
The pinout of the terminals of the transistors 2SB772, 2SB764, 2SB985, KT814 is shown in the figures.
It is impossible to imagine a modern apartment or house without video and audio equipment. This equipment is used every day and therefore breaks down more often than others. There are several ways to repair TVs: send the technician to a service center, call a qualified technician at home, or make repairs with your own hands.
Before you start repairing a TV, you first need to make sure what the problem is. This will also help if you do the repair yourself, and then when the master comes, you will be able to explain the situation to him.
There are several types of malfunctions that can most often be found when a TV breaks down.
The technique does not turn off.In independence, a CRT TV or a modern LCD model has broken down, this malfunction is associated with a blown fuse. Only different models have distinctive details from each other. You should also pay attention to the diode bridge - perhaps it was he who burned out.
In both domestic and imported models, the potential can often go astray, for the function of which the posistor is responsible.
If the plasma TV monitor is broken, then the problem, most often, is interference or drops, light or dark stripes may appear, color changes while watching a program or movie.
The problem may be a broken cord or a faulty outlet.
If we take into account all the troubles listed above, it is worth saying that the most difficult breakdown is considered to be a screen malfunction. For example, light reflections appear on your monitor after the liquid hits the matrix or the TV is hit, then it is better to carry it to the teleservice. Here it will certainly be repaired, and if the warranty period has not expired, then it will be free of charge or at a reduced price.
See also - How to choose a TV for your home in 2018?
You can try to fix some malfunctions of TVs yourself. And it doesn't matter here - these are LCD models, LCD or LED, it is not necessary to call the wizard if you are confident in your abilities. But caution never hurts, because such TV models are not cheap, and without having any repair experience or knowledge in this area, you can only harm and aggravate the breakdown.
Before you start repairing LED or LCD TVs, you must carefully read the instructions, and also study the principle of operation of your model. Anyone, even one far from this field, will understand that the repair of TVs such as LCD or LED will differ from CRT models. In the latter case, you are guaranteed not to run into a faulty PTC thermistor. The main thing here is to determine the problem, why does the backlight not work?
If you are repairing LCD, LED models, then the only difference here will be what kind of backlight is used. If it is an LCD TV, then the backlighting is produced using fluorescent or fluorescent lamps. For TVs, LED backlighting is produced using LEDs. At this point, the differences between LCD models usually end.
VIDEO The breakdown can only consist in the fact that there is no power, in order to check this on an LCD TV, you can do the following with your own hands:
open the back cover of the model;
remove the wires connected to the matrix;
connect the working lamp to the contacts;
there are also LCD models in which more than one light source is provided. In this case, all sources must be tested. Just dismantle the matrix and plug your TV into the network - you can see which LED is the problem.
When a broken lamp in an LED or LCD TV is identified, it must be replaced. This stage requires maximum care from the master, as well as the manifestation of special attention. In some cases, the lamp is removed without removing the matrix, you just need to move the protective elements with a rubber gasket and pull out the lamp with a soldering iron. Similarly, it is necessary to mount a working light bulb. Now we can congratulate you - you did the repair of the LCD TV with your own hands! Just pay attention to one important nuance - the new light bulb must fully meet the parameters and dimensions of the broken one!
To repair TVs yourself, look carefully at the matrix! If there are "unhealthy" streaks here, then the breakage is in the matrix. Have a new part? Then everything is simple! You change it and turn on the TV, if it works, then you have accurately identified the breakdown.
If the reason for the breakdown of LCD TVs is the screen, then it is best to purchase new models of LCD or LED equipment. It is not recommended to change the screen of LCD and LED models, as it is impractical! This also applies to the LCD matrix.
What could be the problem with a malfunctioning plasma TV? If it is necessary to repair plasma TVs, then proceed in the same way as described above. Just adapt it to your specific case. This description can be applied to any model of plasma TV, just stock up on the necessary tools in advance.
Although today most users prefer to use plasma, many still watch programs on more outdated CRT models. Let's find out how to repair a breakdown in such TVs. Below is a step-by-step instruction that will help you repair your electron beam product with your own hands.
If you do not turn on such a device, check first of all the fuses. In these TVs, the back is made up of panels. Therefore, it is necessary to unscrew that part of the panels. Under such panels you will find a board and the power terminals must be connected to the fuse. They are connected to a conventional incandescent lamp, or rather to its base, after which the TV must be connected to the network. In the event that your equipment is in good working order, the lamp will go out after switching on, otherwise, when the fuse has blown, it will either not work at all, or it will constantly burn.
The diode bridge may also break. It should only be borne in mind that it is necessary to regulate and repair it only after making a dial. In this case, not only a multimeter is used, but also a product passport, which indicates the main parameters of this model.
The most difficult breakdown in a TV with a kinescope is a posistor. To check with your own hands, you must first turn off the power circuit, and then turn it on. In this case, the lamp must be monitored. If the work lamp goes out, then it can be said that the posistor is faulty. To make repairs, it is necessary to adjust the resistance of the network and only ventures to change this part.
But not only the matter may be in the posistor, transistors and capacitors burn out in CRT models. The diagnosis of this breakdown can also be made visually. If the condensate is blackened or cracked, then we replace it with a serviceable analogue. Now you know why the TV does not work and how to fix it yourself.
power supply, a la RECOR. The capacity is close to the radiator, the ESR is poor. Nik_Drozd
3259. ERISSON 1401. Defect: does not leave standby mode, does not respond to any remote control,
2804. Erisson 1406 Defect: does not turn on (no standby mode, fuse intact).
3321. Erisson 1460. Defect: does not turn on, the standby indicator does not light up.
2479. ERISSON 1465, chassis 3Y01. Defect: no color in SECAM, black and white in
When you change a couple of STRs worth 500 rubles each at your own expense, then the mania will disappear and you will immediately want to change electric cars of a penny value
I understand a dime a dozen steep here. I will not say anything .. Each forum shines with its ASAMI with devices worth 200,000 each, and in the end they have what is written: wire cutters and a tester
Right. If the capacitor has not “floated away”, it is worth replacing it or not. Could this somehow affect the work of STR?
Of course, I understand that every month they used to wear TVs to change another air condition, but there must be a conscience too.
By the way, for STR-W6553, no matter what state the capacitor is in the mains filter, it will definitely not cause heating, as well as the electrolytes of the body kit, which is alone and then in its power supply.
I will go around the world if they wear it once a month, it is vital that they wear it daily and at least from four devices. 🙂
I have already written more than once that stupid replacement of capacitors is stupidity and mediocrity of a repairman. There are devices and knowledge of circuitry for this, and if the capacitor is intact, there is no need to change it. Capacitor changers bring only profit to the craftsmen and empty the client's pocket a bit.
Good afternoon, in smart TV mode (on the main screen of the smart), the Source button does not work, to switch to another signal source, you have to restore the system, then the smart menu does not turn on, but the TV mode turns on immediately, and the button works, but when you press HOME button, and go to the smart menu, I can't switch back to TV
Most likely, for this model, these are programmers' flaws. However, the Source button is in Smart mode and should not work until you exit it.
erisson 32les73 - when turned on, the LED turns green, the screen blinks with the splash screen for a second and goes out, the LED remains green, can you tell me what could be? Thanks in advance!
The matrix backlight is probably faulty.
Please say I turn on the TV Erison works all the rules and then it turns off itself, which heats up in it and it turns off when cold air gets on it, then it works fine
It is necessary to disassemble and look, probably swollen capacitors.
TV erisson 21f2 turns on cloudy screen the image is slightly visible, white stripes on the diagonal and after 5-10 seconds. turns off. Please tell me what parts need to be replaced !?
Check the power supply of video amplifiers, to replace C425, C520.
Please help, erisson 39LES65, turns off completely after 5 minutes of operation, then the red indicator turns on. I turn it on again and still, 5 minutes of viewing and off
21uf22, after tuning the channels, one channel was tuned to all.
Errison 21UF11. There was a lock (a key in the left corner), pressed the buttons on the remote control, wrote "Turn on in 30 seconds." The TV turned off, now it does not turn on, the duty room diode is on (it does not respond to the buttons on the remote control and on the TV itself.
Tell me, plz. A very strange problem. Erisson 24LEE31T2 TV, does not turn off with the remote control. Rather, it goes into standby mode, but after 1-2 seconds it spontaneously leaves it to work. This happens several times (2-4) in a row, while he calms down in standby mode.
If the TV did not switch from standby to working mode in the first seconds, then this never happens.
We need diagnostics. It can be either a power supply failure or main.
Hello! Erisson TV 21f2, Before that, it turned on and worked normally, then no, there was a hum in the speakers but did not start, now it turns on but there is no image, when you spin the accelerator on TDX, stripes with a white background appear on the screen. What to do?
Check the voltages of the secondary and TDKS.
there is a lot of red on the erisson 2108 TV, what is the reason?
Malfunction of the video amplifier or picture tube.
I ask for help if possible, erisson 20lj02, it turns on, the green LED lights up, there is no backlight. In the inverter, there is a voltage of 12 V on electrolytes 220 x25, silence on the TL494 PWM.
It is necessary to check exactly at pin 12 of the IC. If it is not there, look for where it is lost (a 1-2 ohm resistor may break) and then look for the causes of the break.
I blunt a little, there is a supply voltage at the 12th, there is no 5v reference voltage at pin 14.
Do you have a pinout for the inverter connector? what voltages should come from the board?
It is necessary to check all the important details in the inverter, power transistors, replace the microcircuit, but the metric has nothing to do with it.
Erisson 24LEB15, When you exit the standby mode, the LED turns green, the backlight flashes for a split second and there is no reaction, there is. De-energized about 2 stands. The clock turns on normally until it falls asleep or turns it off from the remote control.
What can I say, first you need to "examine".
Erisson 39les65 TV
And that there are no instructions? Flash drive as formatted in FAT or NTFS.Only FAT support is possible.
Checked it out. The flash drive is formatted in FAT32. By the way, when I just bought this TV, it read a portable disc with films. True, they walked on a small screen, like a probe. Now the disk cannot be found either. There is an instruction.
If you stopped seeing the disk, and now the USB flash drive, then there is probably a problem with the power supply of external devices. It can be either undervoltage (less) or ripple of the 5V stabilizer.
Forum RadioKot
Time zone: UTC + 3 hours [Daylight Saving Time]
JLCPCB, 10 PP prototypes for only $ 2 and 2 days delivery!
_________________
Time zone: UTC + 3 hours [Daylight Saving Time]
Users browsing this forum: stasych and 9 guests
21.) ERC 54sm (ST92185, STV2248C, TDA8174A) Fault: Narrow horizontal stripe 7-8 cm in size, noises are visible. At the output of the TDA8174A, a sawtooth voltage with a swing of several volts with a frequency of 200-300 Hz. Defective in Proc. STV2248C. Replacement.
23.) ERC (chassis 3S10) are available in different housing options. In one, the buttons of the local keyboard are located in the lower part of the case, in the other version - at the top, above the kinescope. A malfunction appeared in the TV with the upper arrangement of the buttons: spontaneous switching from TV-mode to AV. Flushing the tube around the suction cup did not help. I had to pull out the connector connecting the keyboard to the processor and offer customers to use the remote control. The location of the control board in close proximity to the high-voltage bushing of the kinescope leads to a leakage of static charge onto the control board.
24.) ERISSON 14GX37A Fault: after replacing TDKS JF0208-0208C with an analog XINYE, the frame twitches at the top of the screen and red stripes slip. Reduce the power supply of the TA8445K personnel microcircuit from 27v to 21v, for which, install R 40 ohm instead of jumper J14.
25.) Erisson 14GX37. Fault: the image shows chaotic lines in the form of waves. After opening the TV, swollen capacities were found for the line power supply 220x160v (C561), the power supply for video amplifiers 22x250v (C562), as well as for 18 volts 1000x25v (C565). After replacing the containers, the device started working normally. After checking all the output voltages and making sure that they are normal, I safely retired. However, after three days, the TV stopped turning on from the duty room. Coming back to the client, two more inflated containers C563 and C564, both 1000x25v each, were found. True, not a single one of the replaced capacities swelled, is it an echo of a voltage drop, or is the power supply junk? Without thinking twice, I replaced these containers and soldered the entire power supply! After that, the device works normally for three months. True, there is a guess that the electrolytes that are put into these cheap Erissons are of poor quality, which is why they swell after several years of work. My guess was confirmed by the seller of the parts in the service center.
26.) ERISSON ERC-21NI60. Chassis 3S10. Problem: No A / V mode, reduced vertical raster size. Memory failure 24C08. Eliminated by "flashing" the memory chip on the programmer.
27.) ERISSON 1465, chassis 3Y01. Fault: no color in SECAM, black and white image is normal, switching the color system does not give a result. The sekam is assembled on the LA7642N microcircuit, do not rush to reflash the memory, or change the LA7642N, check the strapping of this microcircuit in the form of 1.0x50 electrolytes, one of them, namely in my case the C247 according to the scheme turned out to be dry, I recommend replacing them all in this strapping, if one dried up, then others, too, may be on the eve.
28.) Erisson 2103. Fault: the screen glows blue, with LOH, the image is low-contrast. Green and red are barely present. The output transistors of the video amplifiers of green and red colors turned out to be leaked. After replacing them, the color balance was restored, but the LOX remained and the image was just as sluggish. The 2SA1015 transistor on the PC (reference voltage) also turned out to be broken. After replacing it, everything worked.
29.) Erisson 14GX37A Fault: D1710 often fails in the power supply. After replacing the D1710, the TV worked. But when measuring, it turned out that the voltage on the secondary is 127 volts, at a rate of 110, and is not regulated downward, besides, the D1710 is heated up strongly, which leads to its periodic breakdown. The defect was that the resistance R552 changed the nominal value from 100 kΩ to 132 kΩ.
30.) Erisson 29TJ70. Fault: blue screen and key in the corner. Doesn't respond to any buttons. Treatment: There is a SUB.Page button on the remote control. The button is not used - there is no conductive layer. To use the button, you need to disassemble the remote control. When you press the button once, only the current channel will be displayed (without the possibility of changing the channel), while all kn. other than STAND-BY SUBPage are blocked. Click SUBPage again. All channels, blue screen and key are blocked. Press this button a third time - all locks are removed.
31.) ERISSON 2102. Fault: turns on in operating mode and after a few seconds goes into protection. The capacitor C919 100.0x160v in the power supply unit has lost its capacity.
32.) ERISSON 2120 Fault: does not turn on from standby mode. The power supply unit and line scan are working properly. Detected leak Q005 2SC2216 (tuner tuning control). Replaced and the device turned on. I had to adjust the geometry in the service menu. Entering the service: On the remote control, sequentially press "menu", "menu", "return channel", "sound off."
33.) Erisson 2108 Fault: very faint image. The diode ZD301 is faulty, on the ABL circuit, a leak. After replacement, everything is OK.
34.) Erisson 2108 Fault: there is no color in SECAM, PAL we work normally. A zener diode D205 7.5v flows on the 15th leg of the LA7642N microcircuit.
35.) ERISSON 2120. Fault: when receiving a color image at the top of the image with a “wrinkle”. When you turn off the color from the signal generator, the picture is normal in both PAL and SEKAM. The reason, the SSC impulse is distorted. Replaced the CTV2248C video processor.
36.) ERISSON 1465. Fault: the vertical size is increased, the APCG does not work (the setting is gone), the AV mode does not turn on. The firmware "flew". Memory 24С08 6. I flashed the memory. After in the service mode, I adjusted the geometry. Entering the service: on the remote control, press MENU, AV, ANAL in sequence. Switching modes with the OK button on the remote control, remember the PP button.
37.) Erisson 2103 and the like Fault: it does not turn on, the standby LED is on, a problem in the memory will help a flashing. But if there is no programmer at home at home, then you can put a blank memory on the socket, the TV will turn on, and then in the operating mode, pull out a clean one and insert the old one and switch the channels after that the TV's performance is restored.
38.) ERISSON 1465 After replacing STRG6653 and R600 (0.15ohm) in the power supply unit, check the resistance R610 (680ohm), which is located between the radiator fins. If the resistance is greater (I had 70kΩ), then the power supply unit will work in pulses - (the LED will flash).
39.) ERRISSON 2105 processor: LG863324A video processor: LA76810A Fault: when turned on in the blue screen mode, the screen lights up in red, the picture is poorly visible in the negative. The TV menu is displayed normally. Reason: the problem turned out to be a failure of the 24C04 memory chip. The memory needs to be reflashed on the programmer. Entering the service menu: (MENU), (MENU), (Q.VIEW), (MUTE).
40.) ERISSON 2108 Fault: no image, there is a bitmap but dark. That there is no image, the C104 capacitor (2.2x50v) was found to be guilty, it was near the SCR, and the dark image was all 3 transistors Q931, Q921, Q911 (2SC815Y) on video amplifiers, all 3 had leaking transitions.
41.) Erisson 1406 Fault: no turns on (no standby mode, fuse intact). The voltage across the mains electrolytic capacitor is normal. Outwardly, everything resembles the B / P on the STR-S-ke, when there is no launch after a thunderstorm. Replacing STR-G6653 gave nothing. The reason was the disk capacitor C606: 1nF (its nominal value was 6nF.)
42.) ERISON chassis 3S10 Fault: the TV does not come out of standby mode. B.P. produces 50V at a rate of 110V. Need to replace Q602 (2SC1815) replacement only! checking the transistor with a tester shows that it is working!
43.) ERISSON 2107. Fault: the capacitors in the secondary circuits are swollen, the line transistor and the ULF microcircuit are broken. The circuit is similar to the FUNAI MK8, the V511 transistor (A1015, stands after the optocoupler) heats up as well, the voltage in the secondary circuits after heating the transistor rises significantly.After replacing with KT814, everything became normal.
44.) ERISSON 1401 percents. LC863532C_57P1, video LA76818A. Two devices with identical defects. Fault: does not turn on from standby mode. Breakdown base-collector Q406 2SB764, power key for vertical scanning. And the main reason for the C933 47.0x50V is in the base of the power transistor of the power supply, a la RECOR. The capacity is close to the radiator, the ESR is poor.
45.) ERISSON 2102. Fault: does not turn on, all sorts of hieroglyphs are displayed on the screen. The graphics are skipping. Replacing quartz did not bring any results. Replacement of CTV222S / RC.2A processor required. Installed CTV 222S / V1.3.
46.) ERISSON 21F2. Fault: does not respond to buttons (the power supply unit starts up, all voltages are normal, but does not turn on). I downloaded the firmware from the Internet, flashed a clean m / s - the TV turned on, but a tincture was required in the service menu. It was not possible with the remote control included in the kit. I pulled out the new memory from the working TV, inserted the old one, turned off the TV from the remote control, turned it on - and everything is OK: the TV worked, nothing had to be set up in the service.
Received TV on repair Erisson 29SF10 , chassis 5Y19E. Such a healthy and heavy suitcase. I was not at work at that moment, so I don't even know how the guy covered the TV in the workshop.
He called me and said that the TV was not showing. Well, it doesn't show, so I'll do it. The TV did not turn on. I immediately disassembled it and visually did not find anything. Although I found a burnt Drosselek. I rang it, it turned out to be burned out.
Soldered instead of him another. I turn on the TV, and it stinks and smells burnt. It turned out that the throttle had burned out again.
The line transistor 2SC5841 burned out, although the circuit should be 2SC5299. Here she is carelessness. I would put a 100 watt lamp instead of a load and everything would be whole.
And the line transistor burned out because in the personnel strap there was a hooked capacitor C451 - 35V 100mf. He pulled the throttle and, of course, the personnel chip N451 - LA78041. After replacing the line transistor 2SC5841, a horizontal stripe appeared on the screen of the Erisson 29SF10 TV. Here, then the personnel is also covered.
I changed the whole thing for new details. I connected incandescent lamps instead of a line load and a power supply.
Included, lowercase and personnel plow. I removed the lamp from the line load and left the lamp in the power supply, which I put instead of the fuse. I switched on the Erisson 29SF10 TV again, the pulses are on, it means the TV is working. He took off the load lamp and the TV shows like new.
Everything, repair Erisson 29SF10 finished…
Copyright Gertc.
Subscribe to RSS,
Posted on Tuesday, October 21st, 2014 at 12:50 am Posted in Category Work Offline. Subscribe to comments RSS 2.0, You can skip to the end and leave a response. Pinging is currently not allowed.
Hello dear! tell.
ST1803DFH and personnel STV9302A were replaced (well, piping in litas). the TV set started, but the image is compressed horizontally and there is a thin white stripe at the top of the screen, on the dark part (it glows especially brightly when turned on). how can i fix it? Is it possible to enter the service without a remote control? (no remote control) or is it somewhere on the adjustment board?
It's a shame to throw out a TV that costs 50,000 rubles and more, on the contrary, a cheap LCD panel is sometimes easier to buy than to replace the matrix.This takes on significance in private companies, the staffing table contains a master's cell. It is not surprising that there is a keen interest in repairing TVs with your own hands, the breakdown may be insignificant, the gain is obvious. How not to be electrocuted, not to break the device? We plan to discuss with today's review, we will list the main types of faults.
The percentage of models with a cathode-ray tube is large. It is logical to start with them to consider how to repair a TV, because switching power supplies are considered an integral part of any equipment. Liquid crystals, OLED (organic diodes), plasma. Scanning chips use similar principles. The way of building the image is different, but the element base is similar. Consequently, do-it-yourself TV repair moves along the beaten path.
The equipment contains fuses. Let's reveal a secret: if a force majeure situation (lightning strike, power surge, equipment drop) happens, the protection should break. Almost the end catches up with the microcircuits. Start with the fuse. Of course, if the equipment is devoid of signs of life. In normal mode, the current through the fuse is zero, the repair specialists came up with the fact, put it into service. The burned-out part is removed, a 100-watt light bulb is connected to the terminals. The resistance is relatively high, it will serve as a good current limiter, the electrical circuit will slow down further to burn out.
Note. According to Ohm's law, the power released by a section of a circuit is proportional to the current. By limiting the value, we will avoid burnout of radio components. Actually, this is done by supplementing the circuit with limiting resistors. The light bulb serves the purpose of indication, makes it clear if an electric current is passing. The spiral is heating up, we see the light.
In normal mode, the light will blink, then go out after turning on the TV. Moreover, the device with such an additive works slightly incorrectly. There are two parts that often burn on CRT TVs:
The diode bridge rectifies the current. With a sharp increase in consumption, one branch burns out. Usually two diodes fail. You can determine the suitable ones by dialing. The diode current flows in one direction, in the other the valves are locked. The circuit triangle indicates where the current is going. According to the concepts of circuitry, the current always flows from plus to minus. Accordingly, place the electrodes starting the dial tone.
The second curious detail is a posistor operating on an inductive loop, the task of which is to remove the potential from a cathode-ray tube. Otherwise, a characteristic rainbow appears on the screen due to the violation of the movement of electrons. A thermistor or a loop may burn out. It is easy to check the circuit. You will need to turn off, then turn on the power. If the lamp that used to be on is now out, the problem is in the potential removal circuit. You can test the device, for a while it will be able to work normally without a loop.
How to understand whether the posistor is out of order or the loop is burnt out? First, measure the resistance. The posistor has four inputs. Two form a heating circuit, two - remove the potential. The resistance between the first pair will be 300 - 600 ohms, between the second - units of ohms. If you turn off the outputs going to the CRT demagnetization loop, we will exclude the section from work. The verification technique is simple. If the lamp is on with the loop, but not without, then you will have to look for a new lace. Visually - a thick wire that surrounds the cathode ray tube around the perimeter. To check the posistor with 100% accuracy, take the trouble to evaporate. After turning on the power, observe the action of the light bulb.
For reference. You cannot keep the equipment turned on for a long time with a light bulb that replaced the fuse. The device is defective, there is a large current in it. It is enough to turn on for a second to understand whether the light is on or not. Then unplug the TV plug from the outlet. It will allow you to protect the serviceable elements of the chain from the unusual load.
What else will burn? There is a large capacitor in the power supply at the input, next to it is a power transistor.Both parts are ringing. The transistor breaks through the source-drain transition, although other options are possible. If it is noticed that half of the diode bridge has burned out, it speaks eloquently: the fuse has failed. The type of breakdown of the TV indicates: there is still a malfunction inside. But it has already led to the failure of one branch of the diode bridge. Carry out the diagnostics until the lamp refuses to light up at all. The key sign of a properly working TV is a characteristic hum, which indicates that the line scan has turned on.
Forgot to give general instructions on how to repair your TV. The main board is dismantled for convenience, leaving a chance to get an electric shock even from the switched off device. It seems that no one has died yet, they got burns. You will need to discharge the cathode-ray tube electrode. Located under the rubber gasket. Without touching the metal parts with your hands, pry the rubber with a screwdriver, swinging from side to side, remove the electrode. Discharge the rod onto the body. If you see a ground loop nearby, it is better to go to it. It is clear that for a successful procedure, you need to have a European socket with correctly connected terminals on hand.
Clicks will be heard during discharge. Continue to touch the contact while the phenomenon is observed. Any modern TV set has electronics assembled by one board, which controls the operation. Many radioelements are visually assessed for their integrity. Defective capacitors swell, resistors (active elements) turn black. Darkened resistance sometimes stays good. The defect clearly indicates: the radio element closes the circuit of the broken element.
LCD TV repair is similar to the case of CRT models. The posistor is, of course, absent. It's easy to understand the cause of the backlight breakdown. LCD TVs use two types:
discharge gas lamps;
organic or LEDs.
Gas lamps don't look like cousins hanging from ceilings. Rather white straws. To check the power, remove the back panel to see the wires going into the matrix. Carefully disconnect from the connector, taking a working lamp, check the functionality. It happens that a number of discharge light sources are occupied by the illumination. Take the trouble to remove the matrix, turn on the TV, see which lamp does not work, replace it.
The installation scheme of the illuminators is different. In some TVs, you just need to pull out the lamp from the end without disassembling the matrix. The wires come in from both sides, each covered with a rubber gasket. The protective elements should be pushed aside, the lamp should be evaporated. Installing a new one takes place in the reverse order. Try to choose one that is equivalent in size to the replaceable one. The location of the lamp is lateral, less often the top. It happens that there are two or more illuminators. If a vertical or horizontal stripe appears on the matrix, the scanning electrode most likely burned out. Try to turn on the device with a different, known good matrix to check the assumption.
VIDEO
Replacing crystals on cheap TVs is not cost effective. The cost of a new spare part is more than 3000 rubles. It's another matter if you have a similar broken TV set at hand with a working liquid crystal matrix. Then the replacement is registered. Repairing a TV screen is rarely cost-effective.
There is a typical breakdown of modern TVs: they stepped on a cable. The vein is ripped out, sometimes together with the track on the microcircuit. The digital receiver is represented by a small microcircuit (which needs to be shielded), so the assembly is inseparable from the connector. Carefully dismantle the electronics before repairing. Then use glue, soldering iron to repair the part.Repair of the TV antenna will be required after a lightning strike. Users install cymbals, forget the lightning rod.
Video (click to play).
Plasma TVs are being repaired in a similar way. There is no backlight, posistors, therefore, there are fewer problems!
