How to repair TV itself

It is no secret that the failure of a television receiver can ruin the mood of any of its owner. The question arises, where to find a good master, is it necessary to take the device to a service center? You need to spend your time on it, and last but not least, 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.

General information

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

All TV sets are identical in their design and consist of a power supply unit (PSU), a motherboard, and an LCD backlight module (using lamps) or LED (using LEDs). It is not worth repairing the motherboard yourself, and the power supply unit and the screen backlights are quite possible.

Power supply repair

As already stated design and operation principle of ICE and LCD TVs, regardless of the manufacturer, the same. Of course, there are some differences, but they do not play a significant role in the diagnosis of faults. Often with a problem with BP LCD TV does not turn on at all, with no indication, either turns on for a while, and spontaneously turns off. For example, the repair of the power unit of the LCD device DAEWOO (can be applied to the plasma), which is not much different from the repair of LG TV, as well as Toshiba, Sony, Ruby, Horizon and similar models, is considered.

1. First of all, before repairing the TV, you need to remove the back panel of the device with a screwdriver, unscrewing the screws. In some models for fixing the back wall may be latches are installedBe careful not to break them.
2. Removing the cover, you will see a power supply unit consisting of several modules on the left, and a motherboard on the right.
3. 
4. On the power supply board you can see 3 transformers: the lower one is the choke of the mains rectifier, the upper left (large) feeds the inverter, and the transformer of the standby power supply is on the right. You need to start checking it with him, since it turns on the standby mode of the receiver.
5. Duty Transformer when the device is turned on, the network must produce a voltage of 5 V. In order to correctly find the wire on which you want to measure the voltage, you can use the circuit, and you can see the markings on the housing. In this case, opposite the desired contact is written - 5 V.
   

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

7. Then one tester probe can be attached to the device body, the other to the previously selected contact, and measure the voltage by switching on the TV in the network. In this case, the device shows 1.5 V, instead of the required 5 V. These readings of the transformer indicate that it is working, but not at full strength.The reason may be dried capacitorbelow or swollen - above the transformer.
8. To vypayat worn out parts, you need to remove the power supply board. To do this, first disconnect all the wires and the matrix cable from the inverter and the motherboard. So that in the future, after repairing the power supply unit, not to get confused, where something connects, you can take a picture of them before disconnecting the wires and cables.
9. Now you can remove the entire power supply of the LCD TV by unscrewing the 4 screws. After removing it is very important discharge all capacitorsto avoid electric shock.
   
10. Solder defective capacitors and change them to new ones, observing polarity.
11. The device is assembled in the reverse order: the board is screwed into place, all connectors and cables are connected, the back panel of the unit is closed.
12. Again, we measure the voltage on the transformer of the power supply of the TV (the device should turn on) and see that it has become 5v. Having unrolled the repaired television receiver, you will see that it works.
    

As can be seen from the review presented above, repairing the power supply units of television sets is not such an impossible task. Following this description, you can conduct and repair of plasma TVs.

Power supply in kinescope tv

Repairing TVs with their own hands, having a kinescope, for example, such as: Ruby, Horizon, Sharp 2002sc, LG TVs, as well as repair of the Vityaz TV, begins with a BP test for operation (this is done if the unit does not turn on). It is checked using incandescent bulbs at 220 V and a power of 60-100 watts. But before that, be sure to disconnect the load, namely the horizontal output stage (CP) - connect a lamp instead. The voltage of the SR varies from 110 to 150 V, depending on the size of the kinescope. Must be found in the secondary circuit. CP filter capacitor (its values ​​can be from 47 to 220 microfarads and 160 - 200 V), behind the rectifier of the CP power supply.

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

Now it is necessary to connect the power supply to the power supply unit, and measure the voltage under load. Voltage from 110 to 130 V should be if the tube has a diagonal from 21 to 25 inches (as in the model 2002sc).With a diagonal of 25-29 inches - 130-150 V, respectively. If the values ​​are too highthen a check of the feedback circuit and the power supply circuit (primary) will be required.

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

When undervoltage It is necessary to test secondary circuits to eliminate leaks and short circuits. After that, the power protection diodes of the CP and the power diodes of the vertical scan are checked. If you are convinced that the power supply is healthy, then you need to disconnect the lamp and solder all the parts back. Such a check can also come in handy when doing your own Philips Philips TV repair.

Backlight replacement

Another occurring breakdown of the TV set that can be fixed is the burnout of the screen backlight. At the same time, after switching on the TV 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 trips. That is why there is no image on the screen.

For example, the Sharp LSD TV receiver was taken with this fault, although in this way it is possible to repair Samsung TV, Sony Trinitron,Rubin, Horizon and others.

1. To fix the TV, you need to remove the back panel. For this you need a screwdriver or a screwdriver.
   

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

3. The next step is to disconnect the control panel from the case. You do not need to remove it, you still need it to turn on the device.
   
4. The remaining loops are also required to disconnect. Then it is necessary to remove the case on which electronic boards are fixed.
   
5. Before you remove the matrix, unscrew front frame. Remove the matrix itself and filters, snap off the side fasteners.
   
6. We connect the power and we clamp a few keys to enter service menu. This will turn on the lamp for a while.
7. The figure below shows that after the lamps were turned on, the 5th was inoperative from above. Disconnect it, and replace it with a new one - now all the lamps are on when checking.
   
8. Assembly takes place in reverse order.
9. After that, you need to turn on the television set 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 appropriate line and reset, selecting ok. Now repair the LCD TV set is completed. Tests show that the unit is operating normally.

Thus, you can repair Phillips TV and LG 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 an article about LED backlight repairwhere the whole process is described in detail on the example of the LG TV.

Other causes of TV breakdown

Among the typical and simple reasons that the TV does not turn on, there can be a remote control or no signal from the antenna cable.

Malfunction of the remote control

If a the TV does not turn on with the remoteTo begin with, you need to make sure the batteries are suitable. If they are shrunken, replace them. Often the TV receiver can not turn on because contamination of contacts under the buttons. To do this, you can disassemble yourself, and clean the contacts with a soft cloth from the accumulated dirt. If your remote fell, then maybe 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 you will have to replace it with a new one.

You can learn more about repairing the remote control from the following: video or articles.

No TV signal

When repairing LG, Sharp TVs with LCD displays, Ruby, Horizon with the same screens, often there is a situation when it does not turn on when the device is in perfect working order. It turns out that the reason may be no TV signal in the antenna cable. This happens because of the operation of the noise cancellation protection (on Ruby's TV sets, it was started not long ago), and the unit goes into standby mode. Therefore, if you find your TV in an idle state, do not panic, but you need to check the presence of a signal from the transmitting station.

In conclusion, we can say that when you make a decision about self-repair of a television receiver, 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 the TV master, especially since nobody canceled 220 V, and ignorance of the elementary safety rules can lead to unpleasant consequences.