Hi kipper, it's U13 that is in critically short supply someone needs to replace it with something else going forward I think. Or is that what you're saying? someone could add another kind of interface to the board that's compatible with your keyboard and doesn't need U13? that would be great but I doubt I could. I could copy their schematics and layout though.
I will probably upload the full files tomorrow as I think I have gone as far as I can without access to a physical board. Stedy can upload what he has done when he has finished and maybe make a note of changes here? I mean the hope was anyone who builds on this work would share it here and elsewhere. I've wasted 4 weeks if people just let it die.
I'm quite proud I got this far. I'd never even used KiCad a few months ago.
p.s. if anyone is wondering net U12_1 is ground and U13_1 is VCC for some reason, I asked why earlier in the thread but nobody could answer.