I have some DX7I carts and an ADP-1 cartridge adaptor for sale: -

Cartridges: -

YAMAHA DX1/DX5 ROM A
YAMAHA DX7 ROM 1
YAMAHA DX7 ROM 2
YAMAHA DX7 ROM VRC-101
YAMAHA DX7 ROM VRC-102
YAMAHA DX7 ROM VRC-104
YAMAHA DX7 ROM VRC-106

Let me know if you're interested.