I don't recall anyone else with this issue

[JimKirk]

My new week 52 has a high pitched wine that kind of sounds like it is coming from the power supply.

Machine works otherwise fine.

Is it worth exchanging over this?

I hate to do it because otherwise the machine is acceptable (Not too Yellow)

But the noise does bother me.

[AlaskaMoose]

My new week 52 has a high pitched wine that kind of sounds like it is coming from the power supply.

Machine works otherwise fine.

Is it worth exchanging over this?

I hate to do it because otherwise the machine is acceptable (Not too Yellow)

But the noise does bother me.
Adjust the screen brightness from low to high and see if the adjustment makes the noise disappear. If that's the case, call an Apple technician since that's one of the problems with the iMac screen of some iMacs.

[derbystar16]

I'm on my third iMac that has a high pitched whistle when adjusting the brightness. When the brightness is at complete min or complete max, no whistle. Anything in between causes it.

This will be going back for a FOURTH replacement.