When the weather is hot, the LCD screen is black.

First, after the black screen, if the indicator light of the display is on for a long time, it will not change color or flash (just like normal display), the fault lies in:

1. Generally, there is "ablation" virtual welding in the primary of step-up transformer with high voltage board;

2, or the power tube in the high-voltage board power supply circuit appears "ablation" virtual welding;

3, AD drive board failure, or its power circuit failure;

The important difference between these items is that if the display content can be clearly seen under strong light (or squint), the fault belongs to 1 and 2, otherwise it belongs to 3;

Second, after the black screen, the indicator light is not bright, generally:

1. Virtual welding of power regulating tube base of display power supply part;

This kind of fault can sometimes be temporarily recovered by tapping the display shell gently after the black screen;

2. The thermal stability of the lamp tube becomes worse, and it often takes a while (cooling) to restart;

Third, the indicator light flashes after the black screen (the setting landlord has confirmed that it is the fault of the display), which is generally:

1, the characteristics of a rectifier diode in the power supply part of the display become worse, or the reverse resistance decreases;

2. Soft breakdown of filter capacitor, or increase of thermal conductivity pass rate and leakage current, make the effective output power of power supply decrease;

3. The filter capacitor in the power supply circuit of high voltage board and AD board has serious leakage or poor thermal stability;

In short, the landlord can make his own judgment according to the specific situation of the indicator light.