Be sure to add me to your favorites list Very Large Original Yamaha HS-7T HS-6 HS-4 Electone Organ Original Service Manual / Schematics / Parts List Book, Printed in Japan, 1988. This is a very large original Yamaha service manual for the HS-7T, HS-6, and HS-4 models of Electone organs. This service manual is in very good condition, showing some age, and comes in an original Yamaha Technical Service manual folder in good condition, showing some scribbles, marks and stains. This is one of the largest service manuals I've ever sold, and contains specs, dis-assembly procedure, schematics, circuit board diagrams, parts lists, overall circuit diagrams, and much more for these models. From 1988, made in Japan! 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 AND CHECK OUT MY STORE!