Environmental Causes of LCD / PSU Buzz or Noise?
Hello,
Before I post my own rant about Apple blowing off my noise problem as "it doesn't exist, it's not our problem" I want to determine whether...there may be some truth to it! Hear me out: my 27" developed a buzzing noise identical to one heard on several YouTube videos I've seen where the noise corresponds to CPU temperature and brightness. In my case the noise decreases when he brightness is turned down. Apparently it can be solved by replacing a PSU--if a tech can confirm it, that is.
The noise also goes away if I shut it down and unplug it overnight--at least for a few hours after I reboot it. Then it comes back.
The noise also goes away if I run the FULL Apple Hardware Test. Again, at least for a few hours, sometimes even days. Then the noise returns. It's annoying, especially considering that the machine was whisper quiet for the first year of its life.
After reporting it to Tech Support, they referred me to a local Service Center (not an Apple Store with real techs). They couldn't reproduce it. Of course they couldn't! I had to unplug it and shut it down to bring it in, didn't I? So, Apple Care approved a limited on-site call. Sure enough, the noise was there, loud and clear for the tech to hear. At least someone would vouch for me that I wasn't crazy.
So, I brought it back to the service center. But now, we're back to "we can't reproduce the problem in the shop." I was under the impression they would just ship it back to Apple since it was confirmed as something he wasn't qualified to fix. But Apple won't do that because he can't reproduce the problem in the shop (and apparently they no longer take service shipments of iMacs--isn't that insane?)
All of that aside, I got to wondering--maybe it is something in the house! One thing I showed the tech was how both of my amps were picking up the Mac noise through my guitar (a single coil telecaster) Weird, huh? The Mac is definitely the source, but but the guitar picks it up. This Mac is normally plugged into a grounded outlet on a 20 amp circuit. Is it possible there is something in the circuit, or something else going that can cause an electromagnetic disturbance, if only intermittently?
At least it would explain why they can't reproduce the problem in the shop--different environment! But why? Or more precisely, what?
Sorry if my first post to MacRumors has to be so negative, but I REALLY wanted to believe this iMac was going to be an improvement over my old PC (my ever-so-quiet PC...for all it's other faults) and it makes no sense that this issue is so unique to my situation that Apple can deny any responsibility for fixing it--unless the source something unique to my environment (or maybe I'm really a superhero who gives off electromagnetic waves!)
I have ruled out fluorescent lights. On or off the noise persists.
Leads? Thoughts?