How to momentary blanking a video screen with VGA
 

This might be the wrong place for this but any help would be appreciated.

The application is this:

teleprompter app is running and being auto triggered with SMPTE timecode. The artist only wants the teleprompter to be on screen when he forgets words.

A Video switcher is to slow so I was thinking a momentary switch that might let the sync pass but break the RGB lines or something like that.

I hope someone might have knowledge in this forum.

thanks
fvf