Last night I finally had time to assemble my Deviceside USB->5.25"
 floppy interface.  I decided to do it all slick-like and put the drive
 in the shell of an old Sony USB CDRW.  I have two examples of the TEAC 
DO I take it that there is a PSU in this caee? It doens't try to draw all
the power form the USB port, does it?
  FD-55GFR drive laying around, which is the drive
recommended on the
 developer's site.   I attached one to the ext drive carrier and
 powered on.  The drive head started seeking back and forth, not the
 full travel of the disk, maybe 1/4 of it.  It made a loud, steady
 click and flashed the panel light of the bay, as if it was drawing too
 much power from the little PSU.  However, I went ahead and hooked it
 up and read disks (DOS 1.2mb, AppleDOS and C64 1541) to images.  I
 haven't fully tested the images yet but they didn't error out during
 the read.  The DOS one was mountable in WinImage, the C64 one in CCS64
 (don't have an Apple II em handy.)
 Still bothered by the noise, I attached a Panasonic JU-475-4 drive
 instead.  It was quiet, no blinking light.  I imaged the same disks
 with that drive and that appeared to work fine, too.
 Does anyone know the FD-55GFR well?  It seems to have an auto-sense 
Well enough tohave used them and repaired them. And I have the service
manual for at least one version...
  mech of some kind, and one of the two I have has a
spring-eject (the
 other may have had it too but the spring is missing?)  It seems likely
 that it would click continuously, searching for a disk.  Maybe this is
 normal behavior for this drive and it seems loud because it's open? 
No, it shouldn't do that. If the heads are moving around then either the
controller is telling them to do that, or you have power problems.
This really does sound like a power problem (possibly the drive is drawing
more current than the PSU can supply). Have you tried conencting a
voltmeter bertween the 5V rail and ground? And between the 12V rail and
ground? You can find these power rains on the floppy drive power connecotr
of course (grounds on the middle 2 pins -- black wires most of the time,
one outside one (normally a read wire) is +5V, the other outside one
(normally yellow) is +12V
-tony