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 Yamahaequipment, including the DX7.
Yamaha TX816 with 8 TF1 DX7 blades
currently needs batteries replaced in some blades - 2023/10/17 replaced several
TF1 is equivalent of DX7 first generation. With 8 cards could have 128 note polyphony.