TV power supply circuit diagram: principle of operation, possible causes

Today in the market you can see a variety of TVs. Sometimes, choosing a TV from such a huge selection is not easy. And even more so, to know by what scheme they work, this is generally a "dark forest".

What is the power supply circuit of the TV?

The power supply is almost the most important and main detail in the TV, since the whole device works from it. It produces voltage for the lamps on the TV. The power supply circuit or principle of operation consists of a voltage of 2 semi-rectifier rectifiers. Rectifiers are connected in series. If at least one any part does not work, then malfunctions and defects will affect the entire operation of the system. Therefore, the health of the entire power supply must be carefully monitored and given periodic rest. If the TV does not turn on and the Pover button does not want to work, then this may indicate a corrupted power supply.

The power circuits have a filter on the transformer and capacitor. The network input is protected by a fuse, and if you need to turn off the switch. The transformer is needed for a full load, its voltage remains low, which does not interfere with working capacity and overheating.

The diode bridge goes without a radiator. The voltage of 2 transformers, rectified by it, is smoothed by 2 capacitors, and 3 capacitors filters the flaws of the network. To reduce the voltage in the circuit, a large capacitor is provided.

You don’t need to know anything to fix the TV circuit. Simply adjust the load to the output of 12 volts, in the form of a lamp from the headlights of the car, and set the voltage to 12, 6 volts with the 2 regulator. The resistor should stand so that when the load current stops growing when you turn the resistor slider.

Principle of operation

The switching power supply is characterized by rectification of the mains voltage, and then conversion to high-frequency voltage. It can drop to the required values, straighten and filter. First, current flows to the bridge motor. The voltage limiter immediately acts (protects). Then he goes through the filters, where he is converted. Capacitors are needed to charge resistors. The node starts after the breakdown of the dinistor. Later in the power supply, the transistor is unlocked.

If generation appears, then the diodes will begin to work. They will be connected by cathodes. Through negative potential, you can lock the dinistra. In addition, a restriction is obtained. To prevent saturation of the transistors, there are fuses that work after a breakdown. For the opposite work, you need a transformer. At the output, the current exits through the capacitors.

Possible causes of malfunction

It is important that if the power supply is faulty, you need to understand that it is not always possible to repair. Sometimes you need to replace. There are blocks that simply cannot be repaired, but basically they are replaced with new ones (most often flooded with a compound).

If the TV does not turn on and the LED is on, but there is no transition to sleep mode, there is interference in image and background, there is sound, but does not show the image, then you need to consult a professional to the master.

The reasons for the breakdown:

1. Low output circuits.
2. Defective components.
3. Operation of the TV in unacceptable conditions.
4. The presence of fuel elements, exceeding the norm.
5. Wear parts.
6. Rectifier short circuit.
7. Combustion of a power or key transistor.
8. Understatement of resistance.

When a fuse blows, you need to watch the electronic board. Basically the filter capacitor is swollen. To check the high voltage diodes you need to use a tester. After, you need to insert a new fuse and turn on the unit.

If we talk about all TVs, then the most often weak are filter capacitors. Faulty capacitors are expressed by bloating or leakage of fluid from the housing. To advise the diodes to solder out, view. Check the inductor and diodes with a tester. Defective parts must be changed.

IMPORTANT. It must be remembered that it will be difficult to independently understand the operation and malfunctions of the power supply and make diagnostics without additional equipment.

Repair of the TV includes checking the integrity of the cord, disassembling the receiver and the board, inspecting the unit, checking the soldering points. There is no reason to find out visually, it is necessary to check the operation of the fuse, diodes, capacitors, transistors. If the budget allows, then for a little money the master will fix everything.