Yamaha CS80

On my CS-80, the Ribbon is half-working, and I wonder if I should do 
something about it or just leave it as it is.

The felt is in perfect condition; the spring/wire is only there on 
the right 2/3 of the ribbon; the left 1/3 is missing.
The Ribbon works on the right side, but I can't bend the pitch down 
to the sub-audio range, because the reduced travel.

I try to find out what options I have.
I could transplant the (perfect) ribbon of my CS-60 to the CS-80, of 
course. But I hesitate to do this, because I don't want to such an 
atrocious thing to my CS-60, *and* I don't even like the "feel" of 
the original Ribbon very much (my finger feels sore after a single 
full-range slide!), so I'd rather find a DIY solution for my CS-80, 
which I can taylor to my needs.

But I'd like to really know what's going on, and have a plan about 
what to do, before I ruin the appearance of that CS-80's Ribbon's 
look with its perfect felt.

BTW: How can the wire / spring be broken, and 1/3 be missing, with 
the felt perfectly intact ?!

I know the whole Ribbon apparatus works like a potentiometer, where 
the wiper is normally lifted off the resistive sheet. What I'm not 
sure about: What is the resistive part: The wire/spring, or something 
underneath this?

(a) Spring is just a piece of metal - beneath the sheet is a long 
carbon (or whatever) track.

or 

(b)Beneath th espring there is just a metal conductor, and the spring 
itself is the resistance.

I tend to believe it's (a); or is it (b) ?

JH.