You might be able to use a different chip with the same function... like this one maybe http://www.ti.com/lit/ds/slas061d/slas061d.pdf I have also ordered chips from China when I couldn't find them anywhere else. There are places that will manufacture a small batch for you (at a premium of course)

--- In tr-707@yahoogroups.com , "igotbatwings" <igotbatwings@...> wrote:
>
> So I just picked up a 727 for free as it wasn't outputting sound.
>
> I took it to an authorized Roland repair place and he's isolated the issues to IC31 (40H174, latch), IC5 (HD6303XO, timing circuit), and IC37 (PC624C, DA converter). He also said IC37 would be the hard find and that all the voices checked out fine.
>
> Would anyone know where I could find these ICs, or have had any successful experience replacing them in either a 707 or 727 Would love to get this baby back in action.
>