Could you tell us a bit more, what kind of system are you talking about, there are

many Cisco TelePresence systems, is the screen integrated and from Cisco or is

it a third party screen.

When and how does the blackout occur. Like does it only happen in a call, is it the

complete content of the screen which is off, ...

Often it can be helpful to make a video out of it to better understand how it looks.

I would start with rechecking the symptoms and depending on them for example exchange

the cables.

If all components are from Cisco and you do not get a better answer here and you have

a service contract, you could consider to open a case with Cisco TAC.