Help: using 3.5 external drive on IIc

[ericg@cpd.tandem.com (Eric Goodill)]

Hi,

I have a 3.5-inch external floppy drive (don't remember model number or
name but it has a gray case in case that helps), and it works just fine on
my Mac SE/30 when plugged into the floppy port--reads, writes, and formats
disks.  I take the drive over to an Apple IIc and plug it into the floppy
port.

I then used Apple Utilites Disk version 2.3 (I think), and tried to format
a ProDOS disk in the 3.5-inch drive.  The red LED on the drive came on,
and I heard the head step, but the drive didn't spin.  I waited about 30
seconds before giving up.  I tried it on a few different IIc computers
with the same results.  I did note that once, when I reset the IIc while
it was trying to format the 3.5-inch disk, it became the boot drive when I
did the reset.  In this case, the drive started to spin while the IIc was
trying to boot.  Of course it didn't boot as there was nothing on the
disk.  This seems to indicate that the IIc is capable of spinning the
drive (no missing voltages or pins in the connector, etc.).

Are there any tricks to this that I'm missing?

Cheers, Eric

-- 

Eric Goodill, ericg@cpd.tandem.com, Tandem Computers, Cupertino, Calif.