Speedo error

["Smeins, Larry" <lsmeins@ball.com>]

My 87 5kcst has had a very optimistic speedometer from day one.  The
odometer seems to be right on.  I thought I had a mechanical speedo and
didn't especially want to pull it and have it rebuilt so I put up with
the error.  Now I find I really have an electronic speedo and wheels are
turning on recalibrating it myself.  Where is the electronics for the
speedo located?  Is it possible to get at the calibration components to
change them?  Has anyone done it?  My speedo seems to have a 5 mph
offset from about 35 to 75 mph and then shows an increasing error as
speed increases.  It makes my passengers think I really drive fast and
they are impressed by the speed and quiet of my Audi.

Larry