There are a few floating around, usually they can be found in unexpected places. I have a friend who has one, but he's afriad to power it up. I don't blame him, really. I have a cs-70m that is made out of the same stuff. recordings of it that i have heard peg it to be not too far off. Of course, It doesn't work either. One interesting factoid is that the CS-80 was designed here in america, to be built in japan of course
But when yamaha switched to the DX-7 type stuff, they discontinued the maintenence on the old stuff and the Yamaha repair dealers THREW AWAY bucket upon bucket of filter and oscillator chips that make the CS-series so special.
But make no mistake-Yamaha is and has always been in it for the money. They have absolutley no passion when it comes to sound.