I have a flat screen TV that I have always mounted on drywall using plastic drywall anchors—eight of those has always held it up just fine and I probably could have used just four.
New home is in a 1940 building (New York City), and the wall is not drywall, it’s a wooden board with plaster over it. My searching on the subject suggested that lath & plaster is likely for the time and place, only the wooden board doesn’t look like lath from the photos I have found.
Here is what the interior of the wall looks like, as seen in the cut-out for various cables relevant to the TV:
(Yes, I also wish they had used proper jacks for those wires; the bedroom side of this wall is worse and I’m not yet sure what I want to do about that.)
I can’t get a good photo of the far side of the wall space, but it’s the same kind of board, as far as I can see (which isn’t very but maybe a foot or so) in all directions. It’s not thin strips like I usually see described for lath.
So what is the appropriate hardware to buy for this kind of wall, that will hold the TV securely to the wall? There are some holes in the wall already, looks like they drilled four holes and inserted sort-of-similar plastic pieces past the plaster and into the wood, but I’m not sure exactly what they are (they’re in pretty deep and I can’t see them very well) and what the process is.