Introduction: Now the 2113 TV sets we use are basically LCD TVs on the 5261, that is, the display is a liquid crystal display, which is different from the 1653 previous picture tubes, and the picture is more clear, true and vivid. Therefore, the place where the LCD TV fails is different from the previous TV. Today we will briefly introduce the basics of LCD TV repair. To understand the common sense of LCD TV repair, let’s first introduce the faults that often occur in LCD TVs and the judgment and repair of the faults. This facilitates future maintenance work.
LCD TVs often have a flickering screen, that is, after turning on the screen, the screen turns off when it lights up. But other functions are normal, such as sound, remote control buttons, etc. This phenomenon is mostly caused by the disconnection of the protection circuit of the backlight of the LCD screen, and may be caused by the abnormal voltage of the backlight. Because the most important and most expensive component of a liquid crystal display is the display, a protection circuit is added. There are two main methods of troubleshooting and maintenance. One is to check whether the socket connection of the backlight booster board is normal, and solder the place where there is open soldering. The second is that the socket is not plugged tightly, just plug it tightly.
There is no change after the LCD TV is turned on, and everything else is normal: sound, remote control, etc. This failure requires the following judgments. One is to check the power supply voltage of the backlight circuit. Abnormal power supply voltage can cause this phenomenon. Generally, the large screen is 24V, and the small screen is 12V. The TV manual will be marked. The second is to check whether the backlight switch control signal is high-level start, and whether the signal waveform is normal. Generally, the booster board can be replaced. After the booster board is replaced, the fault cannot be eliminated, and multiple backlights are faulty.
After the LCD TV is turned on, there will be a blurring phenomenon. There are two ways to judge this kind of fault. One is to check whether the digital board contact is normal. If it is abnormal, just open the soldering place. The second is whether there is poor contact in the TV. The maintenance method is the same as above. If the TV has neither display nor sound, check the backlight and sound system, and then determine the fault step by step, and then eliminate the fault. The power light does not light up after the machine is turned on. It may be that the power board is faulty, or the CPU is faulty, and then you can properly replace or repair it after judging it.
The above introduced are several common small faults of LCD TVs, and they are all relatively easy to judge. If you have an ammeter and a voltmeter, you can judge by yourself. However, the power supply must be cut off during the maintenance process to avoid breakdown of the circuit board. Therefore, it is better to find professional maintenance personnel for this fault.
