Apple IIc Plus 3.5" Drive Problem

[Doug Anderson <dougcpa@gmail.com>]

I have a IIc Plus that starts just fine and displays output to the 
monitor.  However, if I insert any 800K ProDOS floppy disk the drive 
read light lights up for one second then goes out and I get the ] 
prompt on screen.  The drive doesn't even act like its attempting to 
read the disk.

Any ideas on what may be causing this?  Seems like if the drive was bad 
it would still at least grind away on the disk trying to read it.