I remember only this scene from what I believe was a horror themed TV show from the '70s.  
I was born in 1970, so I think I watched it between 1973 and 1977? It was in color and it was seen on U.S. television and appeared to be shot on videotape, which is why I say it was a TV show or TV movie. It could have been British also because there was no dialogue in the scene.

In the scene, a medieval suit of armor, like what the old knights wore, is standing in a hallway like you see in castles in horror movies. It seems to come to life and comes walking down the hall and into the room of a sleeping boy, who looked to be about 8? years old and with brown hair, and then carries him back out of the room and down the hallway. This was a very scary scene and had a real creepy feel to it and it was at this time a grown-up said something like 'you shouldn't be watching this' or something like that and turned it off!

I also don't think it was "Dark Shadows", but I could be wrong. I seem to remember it was at night when I saw this. I know the British produced lots of television horror that was shot on videotape at this time.

It was definitely shot on videotape and had the look of a Dark Shadows episode.