Take a small knife and carefully pry the very end of the knob off. The
seam may be hard to see, but there is a cap on the foremost portion of
the knob. Once you get the cap loose that will expose a screw down
inside the knob. Tighten that up and it will probably fix your problem.
No need to dig farther or even remove the unit from the panel.
Careful that the cap is small and can get away from you!

Jamey Jacobs wrote:
The adjustment knob on the lower left of my 302 came loose today. It
was still attached to the metal rod that goes into the instrument and
it appears that a set-screw came loose from the far end of the rod.
Has anyone had this same failure?

Does you know if I can easily repair this or does it require breaking
some quality / calibration seal to get inside the case? I don't want
to take my panel apart thinking I can fix it before I fly Monday, if I
really should plan on sending it back.