Be sure to add me to your favorites list Original Yamaha Overall Circuit Diagram Schematics for DGX-300 Portable Grand Keyboard. Great, original Yamaha set of overall circuit diagrams for the DGX300 model Portable Grand keyboard. This has the overall circuit diagrams, all tucked into an original Yamaha service envelope with holes on one side of it for placing it into a binder if you wanted to do so. The diagrams are in near like new condition, with some minor storage wear on the envelope. These are original documents from Yamaha, printed 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 please check out my Store!