CRT Tube Problem
If you come across color patches problem in CRT Monitor, this indicates the degaussing circuit (posistor) or the CRT tube is at fault. Many technicians do not know how to confirm on which section is the cause of the problem. It is simple and easy with the help of a demagnetizer or degausser. Just degauss the picture tube and if the color pathes is still remain there, chances is the CRT tube already have problem otherwise suspect the degaussing circuit which could be a bad or dry joints in posistor.