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From: spcecdt@ucscb.UCSC.EDU (Space Cadet)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Computer Whine
Message-ID: <4915@saturn.ucsc.edu>
Date: 23 Sep 88 02:46:45 GMT
References: <45900151@uxe.cso.uiuc.edu> <6319@xanth.cs.odu.edu>
Sender: usenet@saturn.ucsc.edu
Reply-To: spcecdt@ucscb.UCSC.EDU (Space Cadet)
Organization: FCIPs (Frivolous CPU Intensive Programs) Ltd.
Lines: 26

}In article <45900151@uxe.cso.uiuc.edu> mcdonald@uxe.cso.uiuc.edu writes:
}
}I just moved my PS/2 model 80 from my very noisy lab to my nice 
}quiet office. I now notice a very odd thing: When idling at the DOS
}prompt the system box makes a loud, high pitched whine. When it
}is actually running a program this ceases. The only explanation
}I can come up with is that it is drawing lower power from the
}power supply when idling, and that the supply is a switching one,
}and hence going to a lower frequency. Then when the power requirement
}goes up, so does the frequency, above the audible range. I this
}correct? Why would the MSDOS idle loop draw less power?
}
}Doug McDonald

	 It may also be your speaker.  My fan and hard drive made enough noise
that I recently made long cables for my monitor, keyboard, speaker, printer,
and reboot switch and put my CPU in my closet.  I really like the relative
quite I have now, but I immediately discovered that the speaker produces sound
even when it is "off".  The loudness and tone vary according to what the
machine is doing, but it isn't related to any i/o (drive, com port, monitor,
etc.)  I assume the sound is leaking from one of the busses and perhaps has
something to do with patterns of memory or card access.

	John DuBois
	spcecdt@ucscb.ucsc.edu
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