Yamaha CS80

According to this site, it appears to be the same part number:
http://www.wdgreenhill.com/manu/yamaha_s.htm

--- In yamahacs80@yahoogroups.com, "papinje" <fernandozarone@...> wrote:
>
> Hi all, 
> after completing (9 months work...) the overhauling of the CS80, that  is amazingly playing now, I have opened a friends' CS60, that doesn't work (as usual... :-)
> I am surprised for finding in all of the the M-voice boards two ICs, named m51623p  and m51628p, instead of the IC8 and IC9  IG00153 and IG00158... 
> Is this normal?   BTW, no sign of desoldering. All of the traces are immaculate.
> The machine is pristine, and only two voice seem to play some sounds...
> If they are correct (a newer  or elder series?) is  any modification needed?
> Thanks 
> 
> Fernando
>