  We consider a simple solution to explain the recent diboson excess observed
by ATALS and CMS Collaborations in models with custodial symmetry $SU(2)_L
\times SU(2)_R \rightarrow SU(2)_c$. The $SU(2)_L$ triplet vector boson $\rho$
with mass range of $1.8 \sim 2$ TeV would be produced through the Drell-Yan
process with sizable diboson decay branching to account for the excess. The
other $SU(2)_L \times SU(2)_R$ bidoublet axial vector boson $a$ would cancel
all deviations of electroweak obervables induced by $\rho$ even if the SM
fermions mix with some heavy vector like (composite) fermions which couple to
$\rho$ ("non-universally partially composite"), therefore allows arbitrary
couplings between each SM fermion and $\rho$. We present our model in the
"General Composite Higgs" framework with $SO(5) \times U(1)_X \rightarrow SO(4)
\times U(1)_X$ breaking at scale $f$ and demand the first Weinberg sum rule and
positive gauge boson form factors as the theoretical constraints. We find that
our model can fit the diboson excess very well if the left-handed SM light
quarks, charged leptons and tops have zero, zero/moderately small and
moderate/large composite components for reasonable values of $g_\rho$ and $f$.
The correlation between tree level $S$ parameter and the $h \rightarrow Z
\gamma$ suggest a large $a$ contribution to $h \rightarrow Z \gamma$ and it is
indeed a $\mathcal{O}(1)$ effect in our parameter space which provides a strong
hint for our scenario if this diboson excess is confirmed by the $13 \sim 14$
TeV LHC Run II.
