Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!cwjcc!neoucom!wtm
From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Computer Whine
Summary: It seems to be the 80386 itself!!
Message-ID: <1355@neoucom.UUCP>
Date: 29 Sep 88 02:29:04 GMT
References: <45900151@uxe.cso.uiuc.edu> <6319@xanth.cs.odu.edu>
Sender: wfd@neoucom.UUCP
Organization: Northeastern Ohio Universities College of Medicine
Lines: 35


I too have an IBM model 80 computer (16 MHz "ancient" version).  I
started out with the IBM 70 meg ESDI drive, but later switched to a
Micropolis 330 meg ESDI drive.  I've used both msdos and Xenix
2.2.2.

The compute emits a quite noticable whine around 12 to 15 KHz,
depending on what is going on in the system.  The noise may be, but
is fequently *not* related to disk activity.

The whine is present with the monitor *off* or on; makes no
difference.

The whine does not come from the vicinity of the power supply; it
is near the bottom of the case.  With the cover off, the sound
seems to be coming from the 80386 and/or 80387 or at least
something very near the CPU chip itself (t'aint the speaker
neither, as I tried unplugging it).

Curiously, as the last poster noted, the whine is just about the
loudest while msdos is in a keyboard wait.

It wouldn't surprise me too much to find that the CPU chip is the
source of sound.  That is a pretty big hunk of silicon realestate
there.  Depending on what the chip is doing, the power drain can
change markedly, thus the whine might actually be due to thermal
effects or piezoelectric effects .. perphaps something like the
solid state beepers on microwave ovens.

There was also an article about "continuously beeping" model 80s
about a year ago in Infoworld.  So there; it isn't your
imagination.  I haven't seen any mentions in more scholarly things
such as IEEE journals, or whatever, yet.

--Bill