It seems like a ground problem, or a capacitor dead, or a dying Power Supply Unit ...
So check that quickly, these are very commun electrical problems and can cause this on your screen.
Have you tried to unplug your floppy drive and HDD as they draw lot of power ?
I still wonder why people use RF or composite connnector nowadays. Since January 1st 1980, most new TV and 15 Khz European monitors were equipped with a Peritel/Scart/EuroConnector with RBG + "nationnal" composite entrance (PAL or SECAM), then in 1986 all new TV must had been equipped with, It also become to be used in Japan and others Asian countries, and in 1990 all have to support PAL (and also SECAM for France) color systems...
At the same time, it also arrived in Africa.
Do you live in these primitives rebel countries like the USA or Australia ? :lol:
