This is fascinating. Most outlets are only reporting the black screen, but DW points out it only lasted for four hours, more a stunt than a shutdown. And the semiosis in the resumption time. Media, like the old shortwave (the budget didn't allow for this trip, but I did have one once, in NYC) can always broadcast on side channels at each frequency.
https://www.dw.com/en/hungary-public-media-reform-begins-with-black-screen-apology/a-77880569
Media is now the central mechanism of political legitimization. The ideas spoken by the news readers already existed in the audience, or the news readers wouldn't have said them in an attempt to curry favor with the audience. The people with these notions then gain a collective identity as a particular audience, and can come to agreement on a coherent (vel non) political narrative, which is to say, an understanding of the mechanisms of power that legitimates the exercise of power.
Democracy used to function differently. It was less susceptible to manipulation, because it had more to do with private judgment than discursive rationality.