Sticky Altimeter

My altimeter "stuck" this afternoon when I was returning to my home field
from SnF. It seemed to work fine until the last 5 minutes of the trip - the
altitudes looked right, but as I descended towards pattern altitude, my eyes
told me that I was lower than the altimeter showed, so I tapped the
altimeter face and its reading dropped by about 1,000'. It stuck at that
position until I tapped it again after landing.

I'll check the static line going to it, but if that isn't the problem, is
there anything else I can do other than send it to a repair station?

Thanks in advance,

KB