"Clicking" II+ power supply

["N.N. Thayer" <nnthayer@hotmail.com>]

I have an Apple II+ whose power supply is a little finicky. Sometimes,
when I turn it on, it causes the speaker to emit a fast clicking noise,
about two clicks per second, and the screen flashes in sync with the
clicks.  If I turn it off, let it sit for a few moments, and then back
on, everything works fine.  Other times, when I turn it on, it'll start
up normally but I'll hear a moderately loud *pop* from right beneath
the power switch.  This in particular scares me.

I've never been inside one of these power supplies but it basically
sounds to me like this one's ready to go at any time.  Should I be
worried about any damage to my II+ that I cannot as yet see?  Could I
perhaps extend the life of the power supply by not using the power
switch directly, but instead employing one of those System Saver fans?