Apple IIGS Joystick Port Problem

["Tempest" <tempest@atariprotos.com>]

I have an odd problem with my joystick port on my Apple IIGS.  It seems
that the joystick won't go right (or rather the games won't detect the
joystick moving right).  At first I thought it might be a bad joystick
(I'm using a MACH III) but it works just fine on my Apple IIe, and I
also tested a standard Apple II joystick (Apple brand) on the IIGS with
the same results.  I then thought that it might be a problem with the
IIGS itself, but I tested it on another IIGS and I have the same
problem.

The joystick tester in System 6.0.1 seems to detect right movement, but
games don't.  So far I've only tested Warlock and most of the Sierra
games, but I'm pretty sure I'm going to have the same problem in the
rest of the games I own.  Is this a known problem?  Is there some sort
of conflict with one of my cards?  My original IIGS is pretty loaded,
but the second IIGS I tested it on was basically empty.  I also tested
a joystick that plugged directly into the paddle port (a MACH II) and
it worked just fine so I'm fairly sure that it has something to do with
the joystick port itself.  

Any ideas?