There was a distinct problem with these circuits blowing up
(after multiple uses) after they’re turned ON and OFF if
capacitor, C2, is not completely discharged after each time
these circuits are turned OFF since an accumulation of
voltage occurs, at C2.

So, I replaced capacitor “C2” with an elevated resistance
which solves the problem. Now, there cannot be any accumu-
lation of voltage at this location whenever this circuit
is turned OFF.