[Coco] FD-501 controller not working with CoCo3?

[Rich Carreiro]

As a born-again CoCo'er :), I've been pulling stuff
out of the attic and acquiring stuff on eBay.

One of the things I have is a FD-501 controller.  I don't
have any FD-501 drives, though.  What I do have (among 
some older, single-drive, vertical units) is a FD-500
drive unit.

Anyhow, when I connect it all together, the floppy works
fine with a CoCo2.  But when I try using a CoCo3, things
simply don't work.

I get the Disk Extended Color BASIC prompt fine, but when
I do any disk operation, the drive turns on, spins for
a couple of seconds (with no "gronking"), and then turns
off followed by the computer giving me an ?IO ERROR.

Any idea what may be going on?

--
Rich Carreiro                            rlcarr at rlcarr.com