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LCD TV viewing process in the irregular three no fault maintenance experience

2018-01-14 12:48:00

Intelligence has become one of the hottest topics in the home appliance industry, home appliances have laid out their own intelligent strategy, whether in the e-commerce or in the entity can see a variety of smart home appliance products. As ordinary consumers, we feel the convenience, safety and speed brought by intelligence, and at the same time, it also brings small troubles: how to repair small failures of intelligent equipment. In order to help more people in need of help, we hereby introduce the continuous home appliance maintenance experience here. Article 165: The experience of irregular three no fault maintenance in the process of LCD TV viewing

Tools/Materials
1

Multimeter, soldering iron, rosin, solder

2

Flashlight or strong light, magnifying glass, screwdriver

Methods/Steps
1

This machine to be repaired for an old customer, because of its age can not carry the TV, so an exception to help its maintenance. This machine fault appears as, irregular black screen (three), normal viewing for one to three days will not appear a failure, but when there is a failure, it will appear continuously at irregular intervals, generally between half an hour and an hour. When there is a fault, the remote control can control the TV switch, and you can see that the indicator light turns from red to blue, but the screen is not bright, no image, and no sound. As shown in the picture below:

2

First, the TV was turned upside down on a flat workbench, but because it was at the customer's home, it could not find a suitable workbench, so it was placed on the dining table. Remove all screws on the back of the TV with a screwdriver, taking care to remove the small screws near the power cord, and remove the small cover. Move the power cord through the hole and remove the back cover. Screws should be piled in a centralized way to avoid loss. After removing the back cover, you can see the internal circuit structure of the TV. As shown in the picture below:

3

Then, according to the fault image analysis, the fault is irregular, sometimes good or bad, indicating that there is no component damage, because the component damage is irreversible. Then the occurrence of such a fault is generally due to poor component performance caused by overheating, or abnormal power supply caused by virtual welding of components. The screen and high pressure plate do not need to be suspected alone, because there is no sound when the fault occurs, so the fault part must be caused by a common part. Next, remove the power supply board that is prone to problems related to the fault and check whether there is a virtual welding situation. Remove all the four corner screws of the circuit board, and remove various connection terminals (plugs) on the board.

4

After the power board is removed, turn it over, illuminate the circuit board with a light source such as a flashlight or strong light, and use tools such as a magnifying glass to observe the solder joints on the circuit board, carefully check whether there is an opening welding image, and focus on checking the connection of each row of wire terminals. It is difficult to distinguish the solder joints with the naked eye, and serious cases may see a ring of black marks like thin lines around the solder joints. However, some are not serious, and can only be observed with a magnifying glass or an electron microscope (dedicated to the circuit board).

5

Therefore, the door does not bring such tools, can only take the method of doubt welding, that is, "rather kill a thousand, do not put a" principle, all doubt like all rewelding again. In order to save time, do not pay attention to the welding process, use a large number of rosin large-area welding method. In this way, although the welding is not beautiful, there are rosin marks on the board, but the speed is fast, and the welding joint is not easy to adhere.

6

After the above welding, the power test machine, if there is still a fault, and then measure the voltage at all levels to check whether there are elements of poor thermal stability. However, the fault of this machine is the virtual welding, because after the welding of the above steps, the test machine found that the fault does not appear, and after vibration and other ways, there is no fault. After a few days of use by the user, the reflection TV is completely fine, and no black screen appears. This shows that the fault of this machine is indeed caused by virtual welding, so far, the LCD TV viewing process of the irregular three no fault maintenance process is all over, the whole process is very simple without replacing any accessories, just a few solder joints with electric soldering iron. If your home TV also has a similar situation, you may wish to try it yourself, perhaps the disease can be eliminated! Why not save $200 for the time it takes to smoke a cigarette?!

Matters needing attention
1

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2

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