Be sure to add me to your favorites list Yamaha Original Service Manual Booklet for the MH100 Headphones with Microphone. This is a very good condition vintage original Yamaha service manual for the Yamaha MH100 Headphones with microphone. This service manual is very brief, 1 page front and back, and has specs, overall assembly and parts list. This is a nice vintage sheet from Yamaha, printed in Japan, from 1988. It would be very useful if you have a set of these vintage headphones to repair, and it's a nice collectable as well! I have 2 of them available at this time. 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. Thank you so much for looking! Check out my Store!