Be sure to add me to your favorites list Original Korg i4S Music Synthesizer Workstation Keyboard Service Manual with Schematics, Parts List, Diagrams and More. Original Korg Document / Booklet from 1994, Printed in Japan. This is an original Korg service manual booklet for the powerful Korg i4S workstation synthesizer keyboard. It is complete and in very good condition, with almost no wear on it. This would be extremely helpful if you need to work on / repair / modify your i4S. Made in Japan, from 1994. 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!