  Theoretical nucleosynthetic yields from supernovae are sensitive to both the
details of the progenitor star and the explosion calculation. We attempt to
comprehensively identify the sources of uncertainties in these yields. In this
paper we concentrate on the variations in yields from a single progenitor
arising from common 1-dimensional methods of approximating a supernova
explosion. Subsequent papers will examine 3-dimensional effects in the
explosion and the progenitor, and trends in mass and composition. For the
1-dimensional explosions we find that both elemental and isotopic yields for Si
and heavier elements are a sensitive function of explosion energy. Also,
piston-driven and thermal bomb type explosions have different yields for the
same explosion energy. Yields derived from 1-dimensional explosions are
non-unique.
