The so-called low-contrast layering is dropped, and the color is not as bright before. 

 

Understand the point of failure errors: 

 

Many people think that after adjusting the contrast invalid contrast control circuit is faulty or has been aging CRT, these views are not quite right. 

 

Cause and Countermeasures: 

 

In most cases this is due to too much dust on the display caused, of course, we can not rule out the contrast control circuit section of a problem, but the possibility is very small, and the amateurs almost impossible for maintenance, so on the screen after cleaning invalid best to find a professional electrical maintenance personnel.