In article <1147656612.398919.134200@j73g2000cwa.googlegroups.com>,
"N.N. Thayer" <nnthayer@hotmail.com> wrote:
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.
When a switching power supply is overloaded, its operating frequency
falls through the audible spectrum until it shuts down. This cycle
repeats, causing a "chirp" sound at a few Hertz.
The pop may be a capacitor discharging.
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?
When I had one like this, I just left it on until I could locate a new
power supply. I've heard of people drilling them open to repair them,
but I assumed the rivets and warning sticker meant me:-)