If the TV fails, it is best to entrust its repair to a specialist. But if you know how to handle a tester (multimeter) and hold a soldering iron in your hands, you can try to repair the TV receiver yourself.
It is necessary
- - tester (multimeter);
- - two 60-100 W incandescent lamps;
- - soldering iron and solder;
- - cross screwdriver;
Instructions
Step 1
TV malfunctions can be of very different nature. If it does not show any signs of life when turned on, first check for voltage in the outlet. If there is, unplug the TV, remove the back cover. Then check the power cord and switch. In the event that voltage is supplied to the power supply, it can be assumed that it is malfunctioning.
Step 2
Take a close look at the power supply first. Look out for darkened resistors and swollen capacitors. A working capacitor has a flat top - if it is swollen, it can be assumed that it is broken. Don't forget to look at the back of the board. Check if there are any breakdowns between the tracks, whether the parts are securely soldered. If outwardly the power supply is working properly, inspect the line scanner - it is the most loaded, malfunctions occur in it quite often.
Step 3
In the event that an external examination of the TV units did not reveal a malfunction, you should start searching for it by checking the supply voltages of the power supply. Chances are you don't have a TV schematic, so find one online. According to the diagram, determine which connector of the power supply goes to the horizontal output stage, and disconnect it (look for a supply voltage of 110-160 V). Instead, connect a conventional incandescent lamp with a power of about 100 watts.
Step 4
If there is no separate connector, it is necessary to unsolder one of the elements of the output circuit of this voltage on the power supply and connect the lamp. When you turn on the power supply for the first time, also connect it through the second lamp. In the event that it lights up brightly, there is a malfunction in the power supply. Look at the diagram which elements of the power supply unit may be faulty (punctured) and directly pass current through themselves to the lamp.
Step 5
The situation when the lamp lights up and immediately goes out or glows weakly, indicates the serviceability of the input circuits of the power supply. The lamp at the entrance can be turned off and further checks can be carried out without it.
Step 6
Start testing the power supply by measuring the voltage across the load (connected lamp). Look at the diagram to see what voltage should be present. It can be indicated both on the power supply connector and on the test points. The supply voltage can be indicated at the output of the primary winding of the line transformer. It should be between 110-150V, depending on the size of the TV screen.
Step 7
If the voltage is significantly higher, in the region of 200 V, check the elements of the primary circuit of the power supply unit responsible for its formation. Pay particular attention to electrolytic capacitors. An outwardly serviceable, but old capacitor may have a low capacitance, which leads to an increase in the output voltage. When low, you should check the secondary circuits of the power supply unit. Pay attention to capacitors and diodes in the horizontal and vertical power circuits.
Step 8
In the event that all voltages are correct, the malfunction should be looked for in other units of the TV. First of all, in the line scan.
