Q: my apple cinema display fan has become louder

Or perhaps it's the speakers, now that I listen again. When I turn the monitor on, there's an audible pop sound, like a speaker firing up. Though I can't be sure.

Interesting, that it seems to get louder when you plug in the power chord. That makes it seem more like a speaker problem than a fan problem. (It's not uncommon at all for speakers to buzz when some extra power is put in the wrong place. For example, in my car, my smartphone sounds great through the aux port--but then if I plug the phone into a power source, my car speakers will buzz).

This might also explain why the sound gets louder when you increase the brightness on yours--when you crank up the brightness, you're sucking more power. Everyone is familiar with the fact that their laptop batteries die faster when they increase the screen brightness. And more power means more speaker buzz.

That said, I still have no idea how to fix it. But now I'm starting to bet that the noise has something to do with the monitor's speakers and the power. Maybe there's a badly coated wire, somewhere. Or some crossed wires.

I'm not at home yet, but when I get back, I'll try turning my brightness up and down, and seeing if it has an effect. I'll try the magsafe thing too.

Alright so I've come home and tested the problem again. The noise I'm hearing is definitely not the fan.

I figured this out in a funny way. I grabbed one of my cat's feather toys and held it under the vents at the bottom of the monitor. The feathers moved in the air from the monitor's fan. By doing this, I discovered that the fan doesn't run constantly. In fact, I could make the fan shut off completely by putting the display to sleep.

When I did this, the feathers stopped moving, but the noise continued. (Which makes perfect sense--the speakers need to continue working even in the display is asleep--many people listen to music on their computers until the display shuts off. The music needs to keep going.)

I'm completely convinced now that the sound I'm hearing is coming from the speakers inside the monitor. I should have known it from the beginning. That tiny 'pop' sound that comes on when I fire up sure sounds like a speaker.

My monitor is actually under warranty still, but I've had some difficulties in getting the Apple Geniuses to replicate problems I've experienced in the past. I'm not at all sure that they will notice the noise I'm hearing, especially in a noisy Apple store. But I suppose I have no choice now but to haul the monitor in and try.

Definitely interesting. And I would probably do it, if my monitor wasn't under warranty. I guess I'll be leaving it up to the Apple techs.

Even though I'm pretty sure that my problem is the speakers, its possible that yours is the fan. Who really knows, without opening it up and looking? There are several things inside of there that can make noise. Hopefully you get it solved without spending too much money.

Thanks for the image and link.

What a pain, huh?