A capacitor that clicks is dangerous; it probably is not that. However, it is possible that the fan becomes caught on ice, so the motor protection is clicking. The fan would only have one speed.
Another possibility is that there is some moisture in the refrigerant or in the pressure sensor lines causing blockage at critical points so the pressures are not correct for defrosts. This could only be found by an experienced heat pump technician or a very lucky guesser.
I would be concerned about how you defrosted the cylinders. An experienced technician would be hesitant and worried when even using warm water to thaw a cylinder; and never would use an open flame.