PSU whine - Not Fan

[chico1st]

I have seen a lot of information around saying that either inductors or capacitors in PSU's can cause whining noises.
All of a sudden my PSU started whining, its annoying it must stop.
The warranty is up so i have to fix it myself.

I have 3 issues
1) how do i find the offending part? I have heard I should use a paper towel roll and my ear... I tried poking parts with a pencil but had no effect.

2) How do i discharge the PSU/caps? I cant get at the cap leads easily. can I just put a 10K power resistor on the AC in/out or ground them?

3) When i find it, if its an inductor i just slather it in nail polish/RTD? What if its a cap, replace it?

 

[zergesys]

Under what kind of conditions does it whine? All the time, even bare-board?

If you want to completely drain the PSU before you go in, which is a must, try plugging in the PSU, flick its off switch, then go to the main 12v rail and put a jumper into the two PowerON pins and hold for a bit. This should drain everything.

I'm kind of iffy on what to do with some components. I usually just replace.