Yamaha CS80

Cheers,

Jonathan

Jonathan,

Duplicating the logic is easy.  The big pain is the voltage.  The Yamaha uses 4000-series CMOS and runs all the digital logic at +8.5 / -6.5 -> 15 volt supply.  It’s offset above/below zero to interface with the analog circuits that run off +/- 15 volt.  No modern chips run at this high voltage.  Even 5-volt is history and 3.3-volt is only kept around for interfacing with older parts.  All the chip guts these days are running around 1-volt.   So, you end up needing tons of level-shifting chips to connect the Ardiuno (or FPGA) to the rest of the logic.  Most circuits I’ve seen use chips that were intended for converting RS-232 (also fairly extinct) like the MAX232.  The chips that were most commonly used won’t work anymore since they convert to +5v TTL.

 David

> On Jan 16, 2018, at 9:39 AM, jonathan4051@... [yamahacs80] <yamahacs80@yahoogroups.com> wrote:
> 
> 
> 
> Has anyone ever looked into modern alternatives for these fragile and rare 40-year old chips? I am wondering if it'd be possible to program an Arduino to handle key coding/assigning and D/A conversion on the KAS and KBC boards.
> Cheers,
> 
> Jonathan
>

Beside what David said - yes, someone did it already: 
http://www.cs80.com/SSK/ Ok, it is not for the polyphonic series, but it 
shows, that is doable, and also that it would provide other advantages, 
like adding MIDI.

On 16.01.18 18:39 , jonathan4051@... [yamahacs80] wrote:
>
> Has anyone ever looked into modern alternatives for these fragile and 
> rare 40-year old chips? I am wondering if it'd be possible to program 
> an Arduino to handle key coding/assigning and D/A conversion on the 
> KAS and KBC boards.
>
> Cheers,
>
> Jonathan
>
>