|发布日期：2020-2-18 浏览次数：86 [返回上一页]
2、LG V6 V7的屏组件的缓冲板是常坏件现象是满屏杂点，也有些是满屏有规律的竖条，这种故障可以更换一对缓冲板(就算一边坏，也是买一对。人家不会卖单个给你)或者测量出哪一块IC坏，更换就可以了。
1. When the machine is turned on, there is no image or sound, the power light flashes to be normally on, and the screen flashes white at the moment of turning on. This fault is mostly caused by the damage of the backlight drive board. However, during the maintenance, it was also found that the light tube in the screen was damaged.
2. When the machine starts for one time, the screen will turn on and the sound will be normal. The first one is that the digital board is not good (the vias are not connected or the IC is not in good contact). The second one is that the wiring inside the machine is not in good contact.
3. The first is that the power board is broken, and the second is that the CPU is not working properly.
4. The light flashes, the CPU bus does not work properly or the power on program IC (BIOS) is poor, and the contact between bios IC and CPU is poor.
LCD TV maintenance
1. High temperature
LCD TV is no more than two ways of placing: wall mounted and pedestal mounted. However, for the same machine type and purchase time, the failure probability of wall mounted machine is higher than that of pedestal mounted machine, and the same failure occurs 1-2 years earlier. In this case, the repaired machine will be equipped with two computer fans to ensure that it will not be repaired due to high temperature within the warranty period.
2. Corrosion resistance
The failure rate of the machines near the kitchen in the concert hall is higher than that of other machines, and their failures are all caused by the corrosion of the metal surface between the connectors, and even the copper eye corrosion of the double-sided board. Of course, the source of this phenomenon is the air quality problem. For the maintenance of this situation, the method of sealing with thermal conductive silicone grease does not affect the heat dissipation is adopted. Of course, the metal of the connector should be rubbed clean.
3. Black spots appear
Almost all LCD screens will have problems of black tape and bright wire. The first thing to fix this problem is to have maintenance conditions. After the maintenance, try to coat more points on the module IC of COF with thermal conductive silicone grease. Because this problem is also caused by temperature.
Common contact with machines and troubleshooting
1. The LCD screen has the most problems (black tape, bright line). In this case, it can't be done without maintenance, only depending on the technology and maintenance conditions.
2. The buffer board of LG V6 V7's screen components is often broken, which is full of screen clutter, and some are full screen regular vertical bars. This kind of fault can replace a pair of buffer boards (even if one side is broken, it is also a pair to buy). They won't sell you a single IC) or measure which IC is broken, just replace it.
3. No matter what kind of LCD screen, y board is the second most likely to be damaged in the PDP machine. After it is damaged, the phenomenon is generally flower screen, full screen color dots, or power supply protection caused by short circuit. The vs or VA voltage is instantaneous, but the voltage value on the screen cannot be reached.
4. The X-board is also a frequently broken component in the PDP machine, which is represented by power on Protection (Fujitsu screen) and dark brightness.
5. The failure rate of logic board is not low, which is common in PDP LCD. Its performance is mostly that there is light on the screen, but there will be no character, no image, or irregular color disorder, lack of color, negative image, etc. Some can't be turned on yet.
6. The common failures of LCD are the problems on LCD screen. Dark band and line are the most common. These problems can be summarized basically. Some can only be repaired under maintenance conditions. Some are due to the high temperature, which leads to the separation of COF and ACF at the connection point of LCD screen. This kind of phenomenon can be repaired by scalding the underlayer heat insulation medium under the flat head soldering iron.
7. In LCD machine, the inverter circuit of screen assembly (high voltage board) is a fault prone part, which shows that there is light when starting up, but there is no light for a while, except for sound (sharp), but the aging and damage of light tube will lead to the protection of high voltage board. The way to judge whether the light tube or the high voltage board itself is to cancel the mean comparison feedback circuit on the high voltage board.
8. Many friends often ask how to repair Sharp's LCD. In fact, it is similar to ordinary LCD. After entering the repair menu, you can see that there is a fault code in the error item. Some of them directly clear the code, and some of them are about to repair the corresponding fault parts.
Common fault judgment of LCD TV backlight
1. The backlight goes out when the LCD screen lights up at the moment of AC power on. At this time, the functions of sound, remote control and panel key control are normal.
This phenomenon is caused by the protection of backlight circuit, and the reason is that the power supply of backlight booster board is abnormal. For CCFL backlight circuit, if a backlight tube is open circuit (usually caused by the open welding of the light tube socket on the backlight booster board or the circuit protection caused by the socket not plugged tightly) or a lamp tube is broken, the above faults can be caused.
2. There is no change in backlight switch, sound, remote control and panel key control are normal.
This fault needs to detect the following working conditions: 1) the power supply of the backlight booster circuit, the common large screen is 24 V, very few use 120 V, and the small screen is 12 V; 2) the switch control signal of the backlight booster oscillator output by the CPU control circuit, the common one is high-level start, most of which is 3v-5v light tube lighting control signal. If the above working conditions are met, the backlight booster can be replaced. If the backlight booster fails as usual after replacement, the backlight tube in the LCD module is mostly damaged.
3. When the backlight is on, it is not on.
It is common for the poor contact between the lamp socket of the backlight booster board and the lamp, and the power supply of the backlight is high or low. In the actual maintenance, there should be no error of 1V in the measurement of 24V power supply digital meter (the 24V voltage output on the power board should be no-load or on load