Here is the original Sanyo Mbc 550/555 manual which came in a ring binder
http://www.eriscreations.com/sanyo/diskimages/Sanyo_MBC555_Manual.pdf
Here is logic of the computer boards and how it all connected together.
Sams computer facts sanyo mbc 550/555 schematics only
http://www.eriscreations.com/sanyo/diskimages/sams-computerfacts-sanyo-mbc-55x-schematics-only.pdf
