Hi Ted, a friend of mine has been fortunate enough to get hold of a 1228 and an 828 as well … what a great sound! I never really knew 
However, they could both do with some fixing up and it would be great to get hold of the schematics if possible. I don’t know if there were circuit revisions but these have black pushbutton caps and black P&G style fader caps. They both have direct outs …
Thanks in advance for any help.
Best Regards,
Dan