OldSynths

i recently acquired a yamaha g10 midi guitar.   what i didn't know when 
i bought the thing is that it uses a proprietary cable.  what i'd like 
to find is the schematics to see how hard it would be to engineer a 
cable that would hook directly into a midi port.   failing that, i'll 
have to find a cable and the matching g10c box for this thing to be 
useful to me.

anyone have any suggestions on where i might find these things?  yamaha 
doesn't appear to acknowledge ever having created the g10/g10c and i 
haven't been able to google anything useful.

anyone with information they would care to share would be greatly 
appreciated!

thanks!