Commodore Pet 8032 connecting to a Commodore 8250 dual disk drive. I haven't had much success here, and it's one of those situations where when it's all put together, it doesn't work. No response from the drive. I tried the standard LOAD "$",8, the DIRECTORY command and shift + run/stop.
4032 I restored last year.
USB-IEC adapter to connect to serial drives from a PC. That was based on xum1541, and that does have the option to connect to GPIB drives. Rather than modify the previous one, I built a new USB to IEEE-4888 adapter.