[morzh]

Well, I take it, foam even of the later production, 79s, 80s is prone to the same problem; the speaker shops specifically describe it as a popular problem and even suggested the name: Refoaming. They all perform the procedure.
But what they show is holes in the foam while mine, same as with others with the same radio, the foam fully fell apart into dust all around the circumference. Good thing I did not damage it by playing it.
Now that it has been re-foamed, it sounds very nice.