responding to
http://www.electrondepot.com/repair/...00-171199-.htm
, John Fanelli wrote:
arl_123234 wrote:

Hello, all. The above referenced ca. 1980s MIDI sequencers (termed
"Disk Composers" by Brother) all appear to use the same
internal 3.5"
FDD. The spindle is belt rather than direct driven. I can't find any
specific belt info for these devices on line except for the FB-100
Brother drive which was intended for use with their line of knitting
machines. I have the MDI-30 and I think a 8.5" or 9"
circumference flat
belt might work but if anyone can provide some additional detail it
would be most welcome. Thanks for your time and comment. Sincerely,
--
J. B. Wood e-mail:

I just replaced the belt on a PDC-100. I got it from
https://www.turntableneedles.com. A 9.8" small square belt worked just fine -
their part # SBS9.8. Cost $5.