Be sure to add me to your favorites list Yamaha PSR-6700 Portatone Midi Keyboard Workstation Original Service Manual Book. Good condition original Yamaha service manual for the excellent PSR-6700 workstation keyboard. It's a very large booklet, as this is a large and sophisticated instrument.The first page of it has some rough spots at the top of it, and there are some general creases and marks on it, but no writing or major tears. The large overall circuit diagram sheet is included as well. This service manual has specs, panel layout, block diagram, MIDI implementation, disassembly procedure, test program, parts list, exploded views, circuit board diagrams, the overall foldout circuit diagram and more. See the photo! This is a manual or document, this is NOT a piece of equipment or instrument. If you have any questions, I'm always happy to answer them. Thanks for looking! Check out my Store!