I already contacted Syntaur and asked.
Basically, the view seemed to be that’s proprietary!
So why would Syntar help the community, since they are a business not a charity… that makes sense and since they have been a good company in terms of being honourable about handling sales and the rest of it I have no gripe with that…
However…
I’m going to make it my personal mission to find out exactly how all of this works and post it online for everyone to get for free!
Because, this has gone on for long enough and I’m completely sick of really good synthesisers not being of any use to increasing numbers of people.
I am not interested in exploiting the situation for money or personal gain and I will get to the bottom of it and help everybody I can for free!
I’m going to make it my personal mission to find out exactly how all of this works and post it online for everyone to get for free because I’m sick of really good synthesisers not being of any use to increasing numbers of people.
Anyone who wants to help me is welcome to contact me.
I think community spirit is more important than commercial interests, proprietary knowledge and basically being mean, to me that’s completely antithetical to the entire synthesiser online community spirit and the right to repair movement!
As soon as I work out how to make this work I will post schematics on open source… For people to print their own.
On top of that I will sell kits strictly at cost price to those who don’t have printers 
If Syntaur want to beat me to it, help me, collaborate, compete or just let me get on with it those are all ultimately positive actions that I welcome.
Come on Syntaur, please do something really cool and collaborate with Fatar to create a new poly aftertouch 61 keybed—- you will get all the money back because so many people need one and the R&D will easily be worth it.
Long live the SQ-80’s Poly AT
JJ