There was this fairly well documented problem up on the Apple site a while ago, it seems to have disappeared...
To cut a long story short, iMac DV's like the one I have had a faulty component somewhere in the back, where the power goes in, which occasionally causes the picture to 'breath' or 'flicker'. In my case, the screen goes wild and the computer shuts off (and will not start up again for several hours).

Now I'm assuming that if Apple would even fix this for me, it'll probably be really expensive?
If it is - is there a way I can correct this myself? Can I just flip the thing open, tighten a screw here and there or what? Or is there some ridiculous part that I need to have that'll cost me my left arm?

Any help greatly appreciated - this problem has gotten worse over the past 2 years and I simply haven't been in the position to have it fixed.

Hi,
I've never heard of this problem, but I would try tightening
a screw - provided you touch only the power supply. Oh
and before you open the computer, touch the pins from
your power supply on the computer with your fingers as it
will get rid of any static electricity in your body and
prevent you from damaging any of the devices in your
computer.

schnub