I now have a Yamaha DX7, and a Yamaha DX7IIFD with Grey Matter E! Card, and a Yamaha TX816 Midirack and an assortment of cartridges. I am working to learn how to create new patches for the DX7. My notes on Yamaha equipment, including the DX7.
Note: My DX7IIFD includes a Grey Matter E! Card. So that may change many of the procedures.