high-pitched noise during bootup

[Dan Williams]

On Thu, 2006-09-21 at 02:09 +0200, Carl-Daniel Hailfinger wrote:
> Hi,
> 
> I have noticed some high-pitched noise during each bootup,
> estimated frequency is >12kHz. Sounds like a bird chirping,
> but with a much higher pitch near the upper hearing range.
> The sound is also quite quiet and can't be heard if any
> fans of other machines are running.
> 
> Could anybody verify my findings in a quiet room without
> air conditioning and other sources of noise? This sound
> gives me a headache and at least one other person can
> hear it, too.

I've heard something like it too, and when I commented on it to MarkF he
said it's normal and is part of the DC electronics stepping down the
voltage (or something like that).  Somewhat like the high-pitched whine
you can hear from the high-voltage flyback transformers in television
sets and other CRT-based displays.  Maybe that's what you're hearing?
Maybe check if it comes from the area around the power plug or not.

Dan

> I would record it if my microphone wasn't so crappy.
> 
> Regards,
> Carl-Daniel
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