  In this paper, we revisit the dimension-7 neutrino mass generation mechanism
based on the addition of an isospin $3/2$ scalar quadruplet and two vector-like
iso-triplet leptons to the standard model. We discuss the LHC phenomenology of
the charged scalars of this model, complemented by the electroweak precision
and lepton flavor violation constraints. We pay particular attention to the
triply charged and doubly charged components. We focus on the
same-sign-tri-lepton signatures originating from the triply-charged scalars and
find a discovery reach of 600 - 950 GeV at 3 ab$^{-1}$ of integrated luminosity
at the LHC. On the other hand, doubly charged Higgs has been an object of
collider searches for a long time, and we show how the present bounds on its
mass depend on the particle spectrum of the theory. Strong constraint on the
model parameter space can arise from the measured decay rate of the Standard
Model Higgs to a pair of photons as well.
