If you know that your video input is good, You may have a bad power supply inside your screen. What type of screen is it? How fast does it cut on and off?
It is a dell screen. model number E193FPc. It immediately cuts off and on. I forgot to add this but when it first started doing this I could tap the computer screen and it would work perfect, then maybe after 5 or 10 minutes it would start cutting on and off again.
You should open it up and check all the capacitors... I would look for any that are bulging or have popped. If you have an ESR meter check them with that too.
I have fixed 2 Dell monitors with similar model #'s as yours, with similar problems. Both times a capacitor was bad in the power supply...
If you know that your video input is good, You may have a bad power supply inside your screen. What type of screen is it? How fast does it cut on and off?
I forgot to add this but when it first started doing this I could tap the computer screen and it would work perfect, then maybe after 5 or 10 minutes it would start cutting on and off again.
Sounds like you have a "dry joint" somewhere on the chassis. A dry joint is a solder connection that has become brittle and has cracked due to constant heating and cooling. All that is needed is to locate the joint or joints and to resolder them.
We had this kind of problem in a computer classroom once. All monitors started to cut on and off. The problem was a wrong screen resolution setting in the operating system. I don't know how a wrong resolution setting can cause such an effect, but changing the resolution to the native monitor resolution fixed the problem. Slapping the screens seemed to work at first, but that was only coincidental.