Home TVs have a variety of problems for a long time, but the most common is that there is no image on the TV after power on. In this case, many people do not know what caused the cause, do not know whether to buy a new one or take it for repair. On the other hand, in the maintenance of televisions, what should we pay attention to? Below, just go with Xiaobian to find out.
Reason one:
There is no sound in the television, but the setting menu of the TV can be displayed on the TV. The problem with the TV may be that there is a problem in the separation of audio from sound to video playback.
Solution: We first test the sound-separation separation first. There is a problem with the separation of sounds. Please ask a professional to come to the door for repairs. Do it yourself. Improper operation can cause your TV to not only have no picture. Even the voice will disappear.
Reason two:
Check whether there is high-pressure sound when the TV is turned on, and high-voltage sound appears on the TV. This shows that the circuit work of the TV is basically normal. Without high-voltage sound, the circuit of the TV may not be activated.
Solution:
The television circuit did not start using the human body induction signal injection method first, and observed whether a bright line on the level had a beating or a phenomenon of widening. Such a phenomenon would indicate that the work of the circuit output was normal and the fault appeared in the field vibration. And the field output signal is transmitted on the circuit.
Reason three:
Check the phenomenon of the TV lamp is not light, the phenomenon of lamp light, slowly adjust the screen rotation while watching the screen, the screen will appear three kinds of conditions: 1, the screen does not change, this shows that the phenomenon of lamp grid cathode voltage abnormal 2, horizontal one line, in this case in addition to the field deflection coil open circuit or solder joints and welding joints outside the virtual solder joint field welding and field transmission signal will also cause failure. 3. A vertical bright line is the open circuit of the deflection yoke and the phenomenon of the joint welding.
Solution:
If the voltage of the display tube is abnormal, first check whether the 200V power supply is abnormal. If the power supply voltage is abnormal, you need to purchase a voltage regulator. Welds on the line must be re-welded to the place where the line was cold-welded, and the open circuit conditions should be adjusted.
What if the TV has no sound? There are many reasons why there are no pictures on the TV. For some small reasons, there is no image on the TV. We can find the problem on our own and repair it. We do not have to trouble others. The specific methods of repairing sounds that do not have images are as follows:
1. Listen to the high-voltage sound of the start-up: If there is a description, the circuit work is basically normal (note that it is basically normal), and if not, the line circuit is not started.
2. Observe whether the display tube filament emits light: at this time, slowly adjust the knob on the high voltage pack while observing the screen changes. There are roughly three situations:
(1) No change, indicating that the cathode voltage of the cathode of the kinescope is abnormal; check whether the 200v visual discharge power supply is normal.
(2) Vertical one bright line because of the open circuit of the horizontal deflection coil or the phenomenon of false welding in the solder joint.
(3) There is a bright line at the level, and there are many reasons. In addition to the open circuit of the field deflection coil or the welding of the welding spot or the welding of the field output block welding, the signal transmission circuit of the field oscillation and the field output may cause malfunction.
Color TV repair precautions
1. It is necessary to figure out the fault condition of the faulty TV before repair. Whether you are repairing yourself or repairing your friends or relatives, this should be considered. Avoid being mistaken for yourself.
2. How to find out the fault condition of the faulty TV during maintenance?
(1) Understand the specific fault phenomenon, the process of failure, whether it happened suddenly or gradually, what is the status, and it is helpful to analyze the cause of the failure.
(2) When helping others to maintain, ask whether the color TV is turned on and whether it has been repaired or not. If you ask these questions, you can determine whether you can observe the power of the TV in front of the owner. To find out the fault condition of the faulty TV, it is better to be able to watch the TV on the front of the owner, and then open the case and observe it carefully.
(3) For the "three-nothing" TV, after opening the casing, it is necessary to pay attention to whether there is any problem with the diameter of the CRT. You can use your hand to sway lightly, because some of the broken pipe diameter will be fixed by the deflection yoke. The webmaster had encountered such problems before. It also depends on whether the circuit board has obvious faults, such as significant breakage, large area scorch, etc.
(4) Observe the faults caused by falling or high voltage due to high lightning or power grid voltage. Observe the component surface and observe the wiring surface.
(5) Some fault phenomena can be heard, such as electrolytic capacitor burst, there will be a kind of oil flavor, high pressure package fire through the shell, there will be a smell of burnt, and so on.