  We review the basic definitions of the direct microscopic formalism (DMF) and
the corresponding model code TRANSNU, to describe pre-equilibrium nuclear
systems, as elements of the grand canonical ensemble. We analyze its
inconsistencies, especially the impossibility of exact solution of the nuclear
many-body problem, and propose solutions.
  We use the strong dependence of pre-equilibrium emissions on the ratio of
transition rates, in code ${\bf \mbox{TNG}}$, to propose a redefinition of the
parameters in the master equation, and obtain smoother excitation functions in
the energy regions where different exciton classes contribute. We compare the
transition rates of TRANSNU with the phenomenological ones for the estimation
the excitation function of a few p-induced reactions on $^{56}$Fe, and obtain
reasonable descriptions for activation energy, local maxima and average
magnitude.
  Despite the inconsistencies and a few remaining numerical problems, related
with non meaningful noises in the strong oscillations of the TST, especially
with the excitation energy and for low exciton number, we find the results of
the present work very promising, indicating that the DFM can be used as a more
precise and physically meaningful approach for the study of nuclear systems in
pre-equilibrium than the traditional statistical models.
