Hi there,
I had a similar problem with the Alesis Datadisk a few years ago.
I bought one off the internet and the drive was broken.
Luckily I had bought this as a spare m/c.
I was so incensed by this state of affairs I had a look at the broken drive which was a Sony circa 1994 and bought a job lot of 2nd hand sony drives from a PC reseller specifying that they had to be dble density and from older pc's.
tested all individually with the Datadisk, and most of them worked fine.
Still have 2 or 3 left, if you want to try a couple , or can send digital foto's so you can inspect the connection and jumper arrangements.
Contact me at home thro
www.a-maze-duo.com

hope this helps