I have one that is in decent shape and works pretty good. When I got it I had to re-glue the center metal part to the cone.

I had to disassemble it earlier in the week and noticed that the cone around the edge where it is bent a bit to be held properly by the frame seems to be separating much like a piece of metal does when it is bent back and forth too many times.

I suspect that I will need a good used or new reproduction cone.

I reformed the warped cone from my E3 by appling some weight to it and brushing a thin layer of epoxy onto the back. Maybe this technique will work in your case if you can somehow hold the outer edge in it's original position long enough for the epoxy to set up. The original cone material is stiff so the epoxy layer shouldn't impede sound quality.

Bruce Webster

Not sure if that will work as the cone around the edge is coming apart. Will post a pic soon as I get one taken.

EDIT: just thought about it and I could try putting some tape on the problem areas as that would hold them together. If it were in a flat part of the cone I'd just glue it, but given it is around the edge near the felt glue won't work good.