[Ti] Weird buzzing...

[Kynan Shook]

There are lots of causes of buzzing, most of them are totally harmless, 
and some of them are not really avoidable.  It could be the inverter, 
or the CPU, or something near the speaker wire.
If you're really curious to see if it's one particular cause (which I 
don't see on the discussions website), you can install the Developer 
Tools, plus the CHUD package (not part of the default installation).  
You might be able to just install the CHUD tools; I'm not sure what 
else, if anything, they require from the dev tools.  Anyway, one of the 
fun little tools is a Hardware preference pane that allows you, among 
other things, to enable and disable your L2 cache (and L3 if you have 
it), and processor napping.  The CPU goes into nap after a little while 
of not being used.  This saves power, and keeps the processor cooler; 
and I've heard a lot more people complaining about fan noise than about 
a tiny little whine.  Anyway, if you uncheck the Nap box and the 
whining stops, then the whining you are hearing is the processor 
turning on and off at a very high frequency.  Just one possible cause, 
but an easy one to detect if you have the developer tools.

If you want to check the inverter, see if the noise changes when you 
change your display brightness, or especially if you turn the display 
off (or if the display is asleep from Energy Saver).  If it changes, 
the inverter is a likely cause.

Anyway, regarding the nap-related whine; I can actually hear when my 
17-inch PowerBook is checking mail, if I'm in a quiet room, because the 
pitch of the computer changes.

John <simplymail at ururk.com> writes:
> Depending on the occasion - in this case mail.app in Panther ONLY WHEN
> I am connected to the internet (via the modem, should see what it is
> like over ethernet) - I hear a buzzing from the upper right-hand part
> of my keyboard (near the power button).
>
> This has happened before in Jaguar when I looked at scrolling "About
> this app" screens (I think iTunes and Quicktime).
>
> Otherwise, I don't hear this buzz.
>
> Any ideas? I would assume it was the LCD inverter, but it happens only
> when a specific "even" happens - not all the time.