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How to repair the basic failure of the LCD screen?

2021-04-19 10:55:00

  In recent years, due to the continuous breakthroughs in the key technology of LCD screens and the continuous decline in prices, LCD screens have completely replaced the dominance of CRT monitors in the PC application field, and have become the preferred standard for major brands and compatible devices. product. The rapid popularity of liquid crystal display products means that for those of us who do technical services, it means that a new learning task is placed in front of us. That is, there will be some failures in the LCD screen. How to solve these failures? Let's talk about it for everyone:

  1. Bright or dark lines on the screen

  is generally a malfunction of the LCD screen. The bright line fault is generally a problem with the cable connected to the LCD screen. The dark line is generally that the main body of the screen has leakage. The above two problems are basically the death penalty for the machine, and there is no repair value, because the price of a screen is too high.

  2, color cast failure

  Generally, you can enter the maintenance adjustment mode for adjustment.

  3. The display will not light up once it is on, but the power indicator will be on.

  Generally, it is caused by abnormal high voltage and the protection circuit is activated. In this case, there is usually a display on the LCD screen. The way to look is "squint". The main point of the overhaul is to compare the repair method. Because, the design of the high-voltage board of the current liquid crystal display is generally a symmetrical design, and there may be basically no damage on both sides. Generally, the old machine is prone to problems with the step-up transformer and the lamp. The new machine has more problems with the protection circuit and process.

  4, flower screen or white screen

  Generally, there is a problem with the drive voltage of the screen. If the drive circuit of the screen is on the main board, it should be a failure of the main board. If the drive circuit of the screen is on the LCD screen, the screen should be replaced under normal circumstances, and the risk of maintenance is very high. of.

  5, the monitor has no power

  This is a very simple fault, which should be said to be very simple. There are two types of internal power supply and external power supply for the general LCD extension. The external power supply is more common. Regardless of the type of power supply, its structure is much simpler than the power supply of crt displays, and the vulnerable ones are generally some small components, such as fuse, input inductor, switch tube, Zener diode, etc. A rare failure is the power failure caused by the motherboard cpu. In fact, the principle of this part is relatively simple, which is to pass the keying board to the cpu, and then output a control signal through the cpu to drive the power conversion integrated circuit to work.