[morzh]

Well, I was afraid of it.
When reading the Radiomuseum thread on this radio by Rudiger Walz, I learned the woofer's cone rippled outside part that connects to the basket rim, and which is made from some sort of foam, disintegrated and the cone was loose.
Today after I put everything back to the chassis, I put it in the cabinet and played it. I heard bad rumbling and I realized I probably have the same problem.
I disconnected the woofer and opened the cloth it is wrapped in.
I saw exactly what Rudiger and the other person who commented on his thread both described.


   
   

Not only that, but the soldering post that connects the wires and was riveted to the basket, cut through the rivet and was loose also.

   

So, the cone is in great shape, so I think sending the speaker to Dave in the Speaker Shop and asking him to supply it with a suitable rippled circle.
I think the soldering post could be just screwed with a small screw and a locking washer.