ASA On Top bug?

I have been having a problem with ASA On Top that has been driving me
nuts. A short drive, admittedly... Anyway, the compass dial around the
ADF doesn't adjust. That is, you can turn the knob, and the dial will
start to move, but it soon snaps back to its original location. Even
this would be much easier to live with if its preferred location had
north exactly at the top, but it seems to want to be a few degrees west
of north.

Anybody know how to deal with this?

Tim