Konka T2989N TV has only one horizontal line in the middle What is the problem and how to repair it

This phenomenon is called a horizontal bright line, and is usually caused by a malfunction of the acoustic scanning circuit.

For the fault of a bright line in the horizontal level, sometimes the pin voltage measured by the multimeter cannot accurately determine the signal condition, and the detection of whether the field signal is normal is very simple, the method is as follows:

Take a battery, lead out two wires from the positive and negative ends, weld one end to the common ground wire, and string a 500 ohm --- a few k ohms of current limiting resistors at the other end to hang in the air, turn on the power of the TV, and quickly take the suspended end away after hitting the field signal foot of the field block after normal start-up, so as to simulate the 50Hz field signal, if the field block works normally, the screen will be pulled apart, if the amplitude changes are small or still horizontal, a bright line is a problem with the field circuit part.

For the field signal, if the differential input is used, one of the two wires is connected to the negative signal end, and then the other end can be touched. The most complicated is to check whether the field signal is distorted, which is generally determined by the screen phenomenon, and the waveform and voltage amplitude of the field scan signal can be determined by the oscilloscope.

In actual maintenance, sometimes it is difficult to judge whether the capacitor is abnormal, because there are two indicators to verify the quality of the capacitor, one is the capacity, the other is the withstand voltage, sometimes the capacitance is normal when the measurement is normal, but due to the weakening of the withstand voltage capacity, it will not work in the working state or the internal soft breakdown, this kind of fault is also a lot, should be paid great attention to, for the fault of insufficient field width of the general field bootstrap capacitor internal leakage and power supply voltage abnormality, which is the focus of the inspection. In addition, the amplitude of the field input signal is insufficient or there is a problem inside the field block. For the old type with field amplitude adjustment potentiometer, the capacitance near the field block is more due to overheating, and it can be replaced by general.

In short, it is important to learn to measure capacitance correctly. Beginners should start with the basics, and be sure to learn them well, which is the key to successful repairs.

Faulty presence scan circuits. It is common for field scan manifolds to become desoldered or damaged. Others include broken field power supply, desoldering or broken coupling capacitors, broken maintenance switches, and broken field deflection coils or loose plugs.

Just take care of the field part.

1. The backlight plate of the TV screen is abnormal.

Solution: Let a professional master disassemble the machine for inspection and maintenance.

2. There is an interference source next to the LCD TV. Solution: Remove electrical appliances and other devices with magnetic field interference next to the TV.

3. The TV circuit is soldered.

Solution:First of all, find out the position of the circuit virtual welding,After finding the position of the virtual welding of the TV,Re-weld the place of the virtual welding,Connect it well to solve the problem of the phenomenon of flickering and dimming of the image。

4. The TV has a long service life, and the aging and deterioration of electronic components or too much dust in the machine will overheat the machine and cause the components to burn.

Solution: Replace the TV with a new one, and also prevent the aging TV from radiating.

5. The picture tube of the TV is damp or aging.

Solution: Disassemble the machine for detection, and then replace the corresponding picture tube.

If this fault occurs to the machine, first measure whether the power supply voltage of the logic board circuit is normal (this voltage is provided by the motherboard circuit.

of). If the above measurement is normal, then measure whether the voltage of each output pin to ground is normal for all DC-DC voltage conversion circuit chips on the logic board.

Item. If the components around the above measurement chip are abnormal, then the problem may be that the main control chip on the logic board is abnormal or damaged.

[Otherwise, it is likely that the screen is physically damaged (i.e., the screen itself is damaged, etc.]).

Hello, can you ask how much it cost you to repair this?

Eliminate the poor contact of each data line interface.

The screen is broken.

Dear, hello, thank you for taking the time to wait for me [Kaimeng Core] First of all, make sure that there are indeed vertical stripes on your TV, which is due to a broken circuit board on the TV screen, resulting in this phenomenon of vertical stripes. Specifically, the circuit board with vertical stripes on your Konka LED 47IS988PD TV is the main board, that is, the main control board (Zao Zhixiang main control board), which is the core component of the TV and is mainly responsible for controlling the functions of the TV. If this motherboard is broken, there will be a problem with vertical streaks, so you can try to replace the motherboard to solve the problem.

Summary. Hello dear, it's a pleasure to serve you. Konka 42-inch LCD TV screen has vertical white line 1Check first to see if there is a problem with the accessories of the set-top box that your TV is plugged into. If there is no problem, then it can be determined that it is the problem of the TV itself.

Hello dear, it is a pleasure to serve you. Konka 42-inch LCD TV screen has vertical white line 1Check first to see if there is a problem with the accessories of the set-top box that your TV plugs in. If there is no problem to know how to dismantle, then it can be determined that it is the problem of the TV itself.

2.Logic board issues. The main reason is that the logic board is damaged, and it can be solved by directly replacing the entire logic book.

3.Problems with screen wiring. It is usually caused by damage or oxidation of the screen cable. Replacing the cable can solve the problem.

4.Display panel issues. In this case, the display panel is damaged. You need to replace the display panel to solve the problem.

If the cathode voltage drops due to the breakdown of the green tube discharge, the fault can be eliminated.

The field doesn't work, it may be that the welding is open, and the insurance is broken, you have a long brain.

It could be that the fuse is burning.

1. Please check if all programs are like this, please check if it is a signal problem.

Konka enterprise knows that to provide you with high-quality solutions, attentive to answer your questions, hope to be able to get you.