Vintage Synth Repair

> Hello:Did you try to google the part number?you might find someone with
> some old stock,Yamaha is a b**** since they don't stock parts for 

Sure did, the only thing I found was some closed Ebay item selling a 
chip for 50\ufffd. Not an option at this point really, need to do a bit more 
googling it seems ;)

On the other hand, digging a bit deeper to the CS-family of synths I 
found this on J. Haible's site:

http://jhaible.heim.at/CSSynth/CS80_VCF_large.gif

and the CS-50 / CS-80 service manuals pretty much explain the pin 
functions in detail:

http://www.therogoffs.com/cs80/manuals/CS80_Service_Manual/42%20-%20M%20Circuit%20ICs.jpg

So I'm left wondering if there'd be enough pointers here to construct a 
clone replacement. There were also some posts from Scott Rider (like 
http://www.the-gas-station.com/messages.cfm?thread_id=46157&lastdays=39758&type=normal&page=2) 
stating that he had reverse engineered the chip for his MOTM-480 module 
but this of course uses V/Oct scaling instead of V/Hz. Not that this 
module would be an option anyway, given the price :). I doubt that Scott 
would like to share the bare chip design of his reverse engineering 
works OR be interested in manufacturing/selling a replacement module, 
but maybe I'll drop him a line or three when my research into this 
subject pulls to a halt.

I really wouldn't want to trash the synth for re-sellable parts, but if 
nothing else comes up I have to give this further thought. After all, 
there's also the low output on osc1 (maybe a bad custom VCA chip?) thus 
sourcing the custom part(s) for that is most likely going to be as big 
of a problem as this VCF chip.

Regards,
.Arto.