Be sure to add me to your favorites list Original Yamaha GC2020BII Compressor / Limiter Rack Mounted Unit Service Manual Booklet / Schematics / More. Very good condition original Yamaha service manual for the Yamaha GC2020BII Compressor / Limiter Rack mounted Unit . This is a full service manual, with specs, block diagrams, panel layout, circuit board layout, several schematic diagrams, full parts list, overall circuit diagram and more. I have a couple of these available, in very good condition and it would be very helpful to work on and repair your GC2020 BII. Original Yamaha document, printed in Japan, from 1988. 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!