Path: utzoo!attcan!uunet!husc6!uwvax!rutgers!bellcore!clyde!watmath!watcgl!daemon
From: daemon@watcgl.waterloo.edu (System Processes)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Computer Whine
Message-ID: <5994@watcgl.waterloo.edu>
Date: 25 Sep 88 20:08:49 GMT
References: <45900151@uxe.cso.uiuc.edu-> <6319@xanth.cs.odu.edu-> <5606@killer.DALLAS.TX.US->
Reply-To: smvorkoetter@watmum.waterloo.edu (Stefan M. Vorkoetter)
Organization: U. of Waterloo, Ontario
Lines: 36

:eywords: 
From: smvorkoetter@watmum.waterloo.edu (Stefan M. Vorkoetter)
Path: watmum!smvorkoetter

In article <5606@killer.DALLAS.TX.US-> jsf007@killer.Dallas.TX.US (Steve Fintel) writes:
->In article <6319@xanth.cs.odu.edu-> rlb@cs.odu.edu (Robert Lee Bailey) writes:
->->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.

			[text deleted]

->I also have a PS/2 Model 80 in a quiet room, and I also get the high pitched
->whine.  In my case, it happens (intermittenly) when the machine switches in

I have an IBM PCjr, with a Racore expansion chassis.  It too whines, 
depending on what it is doing.  Turns out to be the power supply in the
expansion chassis.  Touching various parts (don't try this, switching
power supplies have 1000's of volts in them in places) caused the whine to
stop.  The reason the whine comes and goes is that the power supply will
oscillate (switching supplies are supposed to oscillate) at different
frequencies, depending on the load.  If I do lots of accesses to memory
above 128K, the whine goes away (this memory is powered by the expansion
chassis' power supply) as the load on the power supply goes up.  Similarily
if I access drive B.

I tried to put some silicone rubber on the parts that whine, with no
luck.  Wedging an eraser between the offending component and the heat
sink next to it resulted in no whine, but a smell of burnt rubber.  

I guess I just got used to it by now.  I can still hear it quite clearly
if I focus my attention on it though.

Stefan Vorkoetter