Buzzing PS?

Hi, The Apple /// I picked up last weekend has one annoying flaw, and that is a *very* loud power supply, that seems to get louder the longer the machine is powered up. I think this thing becomes even louder than our 1950s-era Westinghouse refrigerator. (OK, perhaps an exaggeration, but the sound seems to carry farther.) There is nothing obviously functionally wrong with the computer - it boots up fine, there's no wavering or glitching in the display, nothing to say that something might be wrong. Except the buzzing. It makes me nervous. Is this noise normal, or is it a sign that something is about to go kablooie? And if something's wrong, is there any way of knowing which part is about to go? It looks like the power supply should be easy to repair, but I don't know what I'm doing with these things. I know it's been stated here that power supplies should be checked before powering anything up, but I don't really know how to do that, and sometimes I'm just too impatient to see my new toys running. Doug Spence ds_spenc(a)alcor.concordia.ca