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964RSCS
13th September 2005, 11:48 AM
Hi all,

I've noticed for a while now that when I have the power supply connected and turned on, the computer makes a faint buzzing noise.

I had thought it was directly related to the screen, as when I scroll, or adjust the brightness, the noise stops, until the screen is "settled" again. Eg, when I stop scrolling a webpage, the noise returns.

It only happens when I have the power supply connected. Not when running on battery alone, and makes no difference what brightness the screen is set to.

Have others experienced this? Is it normal or something I should be concerned about, and look to get sorted under warranty.

Thanks

The_Customer
13th September 2005, 05:17 PM
doesn't sound normal to me....

i think i would get it checked out...

sounds like a magnetic interference or something...

snax
13th September 2005, 06:20 PM
Where is the sound emanating from? The transformer? I've heard a few of those things buzz before (they should be freely replaced).

964RSCS
13th September 2005, 08:50 PM
Sound comes from top of keyboard/bottom of screen as best I can tell... Maybe from screen itself? Certainly not from the transformer though.

Michae1
14th September 2005, 11:47 PM
I have had two powerbooks now and both have done this as well. There is kind of buzzing static sound coming fromt the speakers which disappears when scrolling.

Also if there is any animation on the screen, you know like some animated banner advertisement, or even the little Apple circle thing that spins around as you are waiting for a page to download from the internet or to check your mail, there is a faint pitter patter from the speakers that corespond to the frame rate of the animation on the screen.

I especially notice it when I'm in a very quiet room which is all the time when I am at home! I must say that it is rather annoying. Glad I'm not the only one. I must admit I didn't notice the part about the power supply source having an influence though.

964RSCS
15th September 2005, 06:08 PM
Yep, that sounds like the same thing, or at least very similar....

Anyone technically minded Mac wise have any ideas/opinions/comments? Cheers

Byrd
18th September 2005, 08:46 AM
I've come across other notebooks, not just Macs, that do this as well. Even on a desktop LCD. It's pretty normal. On my iBook the screen 'hums' when I turn down the brightness - it's probably the LCD's inverter or backlighting that is making the noise.

It's probably also much more noticable because our notebooks are silent - apart from the hard disk there is usually not much else that can be heard.

JB

someonestolecc
19th September 2005, 01:17 PM
I second Byrd I wouldn't worry.

I haven't noticed anything from my pb but my old compaq I couldn't have hooked up to an external sound output and have it plugged into the wall - it'd be clicking away.

Squozen
21st September 2005, 08:54 AM
It's not the screen, it's your processor. Change the processor speed from Highest to Automatic and you'll notice the noise goes away. It's normal and well-documented.

It's not happening when you unplug the power adapter because you have the processor set to Reduced or Automatic when it's running on the battery.