  We performed a high-resolution angle-resolved photoemission spectroscopy
study of the Tl$_{0.63}$K$_{0.37}$Fe$_{1.78}$Se$_2$ superconductor ($T_c=29$
K). We show the existence of two electronlike bands at the M$(\pi, 0)$ point
which cross the Fermi level at similar Fermi wave vectors to form nearly
circular electronlike Fermi surface pockets. We observe a nearly isotropic
$\sim$ 8.5 meV superconducting gap ($\Delta/k_BT_c\sim 7$) on these Fermi
surfaces. Our analysis of the band structure around the Brillouin zone centre
reveals two additional electronlike Fermi surfaces: a very small one and a
larger one with $k_F$ comparable to the FS pockets at M. Interestingly, a SC
gap with a magnitude of $\sim$ 8 meV also develops along the latter FS. Our
observations are consistent with the s-wave strong coupling scenario.
