DIY lcd tv repair

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

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

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

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

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

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

You can try to fix some malfunctions of TVs yourself. And it doesn't matter here - these are LCD models, LCD or LED, it is not necessary to call the wizard if you are confident in your abilities. But caution never hurts, because such TV models are not cheap, and without having any repair experience or knowledge in this area, you can only harm and aggravate the breakdown.

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

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

The breakdown may consist only 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 protection 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.

Photo of the TV power supply

Among all the malfunctions, the repair of power supplies takes the first place. In the article "TV Power Supply Malfunctions" I described typical power supply failures. In this article I want to describe the work and repair of power supplies in more detail.

You probably need to start with how to check the power supply after repair, so as not to cause it to break again. Although this method is considered controversial, I find it very effective.

So after repairing the power supply, you need to solder a 150-watt light bulb into the fuse break (it can be 100, but there may be a false glow), and into the B + circuit break (line scan power 95-145 volts, you can just cut the track) solder the light bulb 40-60 watts. Please note that some power supplies will not start at light load.

This system works like this. When you turn on the network after repairing the power supply, if it is working properly, the first light bulb at the moment of charging the network capacitor (100-220μF 450V) lights up and goes out as it charges. A weak glow remains. A 60-watt light bulb glows according to the voltage in the floor.

With a faulty power supply, a 150 W lamp glows with full incandescence. In some cases, this saves the transistor, microcircuit from repeated failure of key elements.

In the second method, the power transistor of the power supply is not soldered and the level and shape of the signal coming to it is analyzed using instruments (oscilloscope, multimeter).

In the description, I will rely on the diagram below.

Malfunctions can be caused by:

We check for a short circuit the elements of the mains filter, rectifier, thermistor - demagnetization system, the key and the elements of its strapping, as well as the key microcircuit (if the power supply is built on it).
When you find a faulty element, analyze the reasons for its failure. Failure of the transistor can be caused both by a voltage surge in the network, and by drying out of capacitors in the primary circuits.

The power supply does not turn on, the mains fuse is intact.
It should be checked for breakage: mains filter, rectifier, PWM - modulator.
Start by checking if the mains capacitor C has a constant voltage of about 300V (if not, look for a break in the mains filter, and also check the resistor R.
If there is + 300V on the capacitor C, check if it reaches the key transistor. You should also check the primary winding of the TP mains pulse transformer for breakage.
If all the elements are in good order, and the power supply does not turn on, it is necessary to check the arrival of pulses to the base (gate) of the transistor.
Also check the trigger R circuitry, usually high resistance resistors.

Check: the elements of the secondary rectifiers of the power supply, the loads of the power supply for a short circuit, the elements of the protection system (monitoring circuits for the output voltages), feedback circuits (modulator).
With the secondary circuits and their loads, I think everything is clear, it is necessary to check the rectifiers (diodes) and filter capacitors.
In the protection circuits, check the optocoupler and its piping.

With regards to the feedback circuits, check the zener diodes, diodes, capacitors (usually 4.7-10- 47 microfarads).

Network capacitor, capacitors of the PWM strapping, serviceability of the optocoupler and its strapping.

In this case, proceed as follows:

• check the soldering of the power supply elements for ring cracks;
• check the elements in the hottest places on the board by identifying them by blackening.
• In the event that a malfunction manifests itself when the TV is warming up, it is possible to localize the faulty element either by cooling (cotton wool soaked in acetone, alcohol), or to speed up the occurrence of a malfunction by provoking it by heating one or another element with a soldering iron.

Hello! Please help me choose an analogue power supply unit (Wene-wn220a-3 24V 7A) for the Chinese TV no. Found a similar one to ebay, but I'm not sure about the insides. And what parameters should be used to select an analogue?

Two parameters are needed: 1) Voltage. Should be similar, in this case 24 V. 2) Amperes. In this case, 7 A. This parameter should be at least 7 amperes, but it should be borne in mind that the larger this number, the more expensive the power supply will be.

tel JVC-AVG14T. When turned on from standby mode, an image appears. and stars.and after 5 seconds everything goes out while the green LED blinks at a frequency of 1 time per second. and does not turn on anymore. It is necessary to turn off the PCN, then everything will be repeated. Changed all the electrolytes in the B / P, optocoupler, zener diode and transistors near it, help! THX.

It is necessary to check the diodes of the secondary circuits, horizontal scanning and vertical scanning.

help Blow fuses on TV Meredian Model TK-5411

The power supply does not start and the light diode does not tell where to look for the cause. Tv polar platform Т08-29к

Doesn't say anything, let's model.

Hello!
The power supply unit is assembled with a key on a composite field, a VESTEL VR2106TS TV, a chassis on an AK-36 tr-re, if I'm not mistaken. Symptoms of malfunction: short-term periodic start of the power supply unit (clatter), while, in time, a whistle is heard, the power-on indicator LED blinks red.
How would you start troubleshooting? With the search for a short circuit in the load of the tr-ra, or a malfunction in the piping of the shim controller?

I would start looking for a fault in the secondary power supply unit, line and personnel.

can parallel to the lamp be switched on on the tra-tor 2 winding, having previously turned off the scan with the output stage and tdks?

Quite right. The light bulb is soldered to the plus of the capacitor 100 microfarads * 160v and the case (minus) of the chassis, track on a line or cut off the power or evaporate the transistor

In the power supply, the lamp 60-75 -95-150w lights up and immediately goes out, which means that the power supply is normal! (40w) I connected a light bulb in series from the trance, then the second end to the choke, those to the capacitor - maybe it is necessary, most likely after it (filter) I think that after the air conditioner am I right or not? thanks for the answer!

Hello! Tell me, after repairing the power supply, I put a light bulb in the break of the mains fuse and it began to start a horizontal scan, but intermittently (extinguished) the lamp and naturally when the start goes out! lamp 60 W and 100 I am afraid to put was the incident burned already on another TV set a bunch of tr-ditch and micro-circuits! It makes no sense to put a lamp in a line of 60 W, because there is a launch - you can even hear it! thanks in advance!

In place of the fuse, a lamp of 150 - 200 W, in a line of 40 W. Most of the line transistors have Pout - 50 watts. Disconnect the line all the same and see if it turns off. If there is, then the problem is in the power supply, no, then in the line.

repair of the TV's power supply still takes second place after the line

A huge THANKS to the author for the material. 111

Guys help me shorter on the Odeon LTD-150D TV malfunctions in the power supply, it seems to me that the problem is in the transistor, tell me where to go with the question?

If there is no knowledge in electronics, then definitely go to the workshop.

Yes, at the expense of the capacitor, I agree, I was poked into my little finger by a good 400V.

I checked all the elements are in good order and the voltages are still underestimated what else to check

Does winding 2 work for itself?

Winding 2 monitors the mains voltage and generates a feedback signal proportional to the secondary voltages.

When repairing the power supply, be sure to discharge the line capacitor. Its charge may damage or shock something.

When diagnosing television devices, it takes immeasurably more time to find a faulty component than to replace it, especially if the search for a defect is carried out on its own, and not by a professional TV technician. Of course, it is more logical to entrust the repair to a specialist who has experience and extensive practice of this kind of work, but if there is a desire, skills in handling a soldering iron and a tester, the necessary technical documentation in the form of a circuit diagram, you can try to fix the TV at home yourself.

The power supply unit of a modern TV, whether it is a plasma panel or LCD, LED TV, is a switching power supply with a given range of output supply voltages and rated power supplied to the load for each of them.The power board can be made as a separate unit, which is typical for receivers of small diagonals, or integrated into the television chassis and located inside the device.

The characteristic signs of a malfunction of this unit are as follows:

• The TV does not turn on when I press the power switch
• Standby LED is on, but no transition to operating mode
• Kinks and streaks in the picture, background sounds
• There is sound, but there is no image, which may appear after a while
• It takes several attempts to turn it on for a normal picture and sound to appear

Let's analyze the circuitry of a standard power supply and its typical malfunctions using the ViewSonic N3260W TV as an example.

To fully view the diagram, you can open it in a new window and enlarge it, or download it to your computer or mobile device.

The first thing to start with is a thorough visual inspection of the board with the device turned off from the network. To do this, the unit must be dismantled from the TV by disconnecting the connectors, and be sure to discharge the high-voltage capacitor in the filter - C1. In the blocks of this series of TVs, the electrolytic capacitors of the filters of the secondary power supplies often fail. They are easily diagnosed by a swollen top cover. All capacitors, the appearance of which is in doubt, must be replaced immediately.

The standby unit is made on IC2 (TEA1532A) and Q4 (04N70BF) with 5V output voltage stabilization elements on IC7 optocoupler and controlled zener diode ICS3 EA1. Absent or underestimated voltage at the output of this node, measured on capacitors CS22, CS28, indicates its malfunction. The experience of restoring this section of the circuit shows that the most vulnerable elements are IC2, Q7, ZD4 and Q11, R64, R65, R67, which need to be checked and replaced if necessary. The performance of the parts is checked by a tester directly on the block board. At the same time, dubious components are soldered and tested separately, in order to exclude the influence of neighboring circuit elements on their performance. IC2 simply needs to be replaced.

If there is a 5V voltage at the output of the standby circuit, a red LED on the front of the TV lights up. At a command from the remote control or a button on the front of the TV, the power supply should go into operating mode. This command - Power_ON - in the form of a high potential of about 5V comes to pin 1 of the CNS1 connector, opening the keys on QS4 and Q11. In this case, supply voltages are applied to the IC3 and IC1 microcircuits, transferring them to the operating mode. On the 8th pin of IC3 directly from the collector of Q11, on the 12th pin of IC1 through the switch Q9 after starting the PFC circuit. The performance of the Power Factor Correction circuit is indirectly determined by the voltage increase from 310 to 390 volts measured across C1. If there are output supply voltages 12V and 24V, then the main source on IC3, Q1, Q2 functions in normal mode. Practice shows the low reliability of the UCC28051 and LD6598D in critical conditions, when the filtration of secondary sources deteriorates, and their replacement is routine.

Summarizing the experience of repairing television power supplies, it should be noted that the weakest link in their composition are filter capacitors, which lose their properties and nominal parameters over time. Sometimes the faulty "container" is visible by the swollen lid, sometimes not. The consequences of poor filtering of the rectified voltage can be very different: from the loss of the power supply itself, to damage to the inverter elements or a software failure on the memory chips on the motherboard.

It is very difficult to independently figure out all the causes and consequences when repairing a power supply unit of a modern TV, to diagnose it correctly without special tools and devices.Our advice in such cases is to call a professional TV technician. This will not hit the pocket hard at the current low prices for the repair of television equipment and will save time.

Note! Small pictures are clickable.

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

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

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

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

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

Measurement is taken first open circuitby connecting one probe to the found contact, and the other to the cathode of the diode on the radiator. In this case, there is no break.

Further, one tester probe can be attached to the body of the device, the other to the previously selected contact, and measure the voltage, having previously connected the telly to the network. In this case, the device shows 1.5 V, instead of the required 5 V. Such readings of the transformer indicate that it is working, but not at full strength. The reason may be dry condenserlocated below, or swollen - above the transformer.

To remove the parts that have become unusable, it is necessary to remove the power supply board. To do this, first disconnect all wires and the matrix cable coming from the inverter and the system board.So that in the future, after repairing the power supply, you do not get confused where what is connected, you can take a photo of them before disconnecting the wires and loops.

Now you can remove the entire LCD TV power supply by unscrewing the 4 screws. After removing it, it is very important discharge all capacitorsto avoid electric shock.

We solder the defective capacitors and replace them with new ones, observing the polarity.

The assembly of the device takes place in the reverse order: the board is screwed into place, all connectors and cables are connected, the rear panel of the unit is closed.

We again measure the voltage on the transformer of the TV's power supply (the device should turn on) and see that it has become 5v. When you unfold the repaired TV receiver, you will see that it works.

As you can see from the review presented above, repairing TV power supplies with your own hands is not such an overwhelming task. Following this description, you can also repair plasma TVs.

Do-it-yourself TV repair with a kinescope, for example, such as: Rubin, Horizon, Sharp 2002sc, LG TVs, as well as the repair of the Vityaz TV, begins with checking the power supply unit for operability (this is done if the unit does not turn on). It is checked using incandescent bulbs for 220 V and a power of 60-100 W. But before that, be sure to disconnect the load, namely the horizontal output stage (SR) - connect a lamp instead. The CP voltage ranges from 110 to 150 V, depending on the size of the tube. Must be found in the secondary circuit SR filter capacitor (its values ​​can be from 47 to 220 microfarads and 160 - 200 V), which stands behind the SR power rectifier.

To simulate the load, you need to connect a lamp in parallel to it. To remove the load, for example, in the popular Sharp 2002sc model, it is necessary to find and unsolder the inductor (located after the capacitor), the fuse and the limiting resistance through which the CP stage receives power.

Now you need to connect the power supply to the power supply unit, and measure the voltage under load. The voltage should be between 110 and 130 V if the CRT has a diagonal of 21 to 25 inches (as in the 2002sc model). With a diagonal of 25-29 inches - 130-150 V, respectively. If the values ​​are too high, then it will be necessary to check the feedback circuit and the power supply circuit (primary).

It should be noted that electrolytes dry out and lose capacity during prolonged operation, which, in turn, affects the stability of the module and contributes to an increase in voltage.

When the voltage is too low it is necessary to test the secondary circuits to exclude leaks and short circuits. After that, the diodes for the protection of the power supply of the SR and the diodes for the power supply of the vertical scan are checked. If you are convinced that the power supply unit is working properly, then you need to disconnect the lamp and solder all the parts back. This check can also come in handy when doing DIY Philips TV repairs.

Another common breakdown of the TV that can be eliminated is the burnout of the backlight lamp. In this case, the TV receiver, after switching on, flashes the indicator several times and does not turn on... This means that after self-diagnosis, the device notices a malfunction, after which the protection is triggered. That is why there is no image on the screen.

For example, a Sharp LSD TV receiver with this malfunction was taken, although in this way it is possible to repair Samsung TVs, Sony Trinitron, Rubin, Horizon, etc.

To fix the TV, you need to remove the back panel from the TV. This requires a screwdriver or screwdriver.

Next, you need to be careful disconnect loops from the matrix.

The next step is to detach the control panel from the case. You do not need to remove it, you will still need it to turn on the device.

The remaining loops also need to be disconnected. Then it is necessary to remove the housing on which the electronic boards are fixed.

Before removing the matrix, unscrew front frame... We remove the matrix itself and filters, snap off the side mounts.

We connect the power and hold down a few keys to enter service menu... This will keep the lamps on for a while.

The figure below shows that after turning on the lamps, the 5th from the top turned out to be inoperative. Disconnect it and replace it with a new one - now all the lamps are on when checking.

The assembly takes place in the reverse order.

After that, you need to turn on the TV receiver and enter the service menu for reset lamp error counter... If this is not done, the device will not work. Entering the menu, you need to find the corresponding line and reset by selecting ok. Now the repair of the LCD TV set is finished. Tests show that the unit is operating normally.

Thus, you can repair the Philips and LG TV with your own hands, and other LCD panels, as well as devices with LED backlight (LED). Owners of the latter type of devices should read the article on repairing LED backlighting, where the whole process is described in detail using the example of an LG TV.

Among the typical and simple reasons that the TV set does not turn on, there may be a remote control or a lack of signal from the antenna cable.

If the TV does not turn on with the remote control, first, you need to make sure the batteries are good. If they are shrunken, replace them. Often the TV set cannot turn on due to contamination of contacts under the buttons. To do this, you can disassemble it yourself, and clean the contacts with a soft cloth from accumulated dirt. If your remote control has been dropped, it is possible damage to the quartz emitter... In this case, it must be replaced. Well, if you filled the remote control with water or some other liquid, and it did not work after disassembling and drying, then it will have to be replaced with a new one.

You can learn more about fixing the remote control in the following video or article.

When repairing TVs LG, Sharp with LCD display, Rubin, Horizon with the same screens, a situation often arises when it does not turn on when the device is in good working order. It turns out that the reason may be no TV signal in the antenna cable. This happens due to the operation of the noise reduction protection (in Rubin TVs, they began to install it not so long ago), and the unit goes into standby mode. Therefore, if you find your TV set inoperative, you should not panic, but you need to check the presence of a signal from the transmitting station.

In conclusion, we can say that when you decide to repair a TV set yourself, you should soberly assess your abilities and knowledge in this matter. If you do not feel confident, then it is better to entrust this matter to a telemaster, especially since nobody canceled 220 V, and ignorance of basic safety rules can entail unpleasant consequences.