[Amps] How to know when filter caps begin to fail

[Jim Garland]

My experience is that the only time electrolytic caps explode is either when
the polarity is backwards or when a rectifier diode fails and AC appears
across them. I've found other age-related failures to generally be more
benign. Generally they just lose their capacitance but don't start
conducting. Now tantalum caps are another story. They almost always fail by
short circuiting, sometimes catching fire.
73,
Jim W8ZR