Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!umich!samsung!usc!elroy.jpl.nasa.gov!peregrine!ccicpg!boink!harald
From: harald@boink.UUCP (Harald Milne)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Dust in the Box
Keywords: dust, fans, cooling
Message-ID: <562@boink.UUCP>
Date: 26 Jun 90 19:20:09 GMT
References: <13405@netcom.UUCP> <7394@dayton.UUCP> <48743@iuvax.cs.indiana.edu>
Organization: Independent Software Solutions, Anaheim, CA
Lines: 60

In article <48743@iuvax.cs.indiana.edu>, chiuk@iuvax.cs.indiana.edu (Kenneth Chiu) writes:
> In article <7394@dayton.UUCP> jad@dayton.DHDSC.MN.ORG (J. Deters) writes:
> >What I did was to disassemble the power supply cabinet, and turn the fan
> >around so it blew IN to the power supply.
> 
> Is there any particular reason why the Amiga comes with the fan sucking
> out instead of blowing in?  It seems that having dust being pulled in
> through the disk drive openings is a bad idea.

	I could not agree more. It is bad enough with the 3.5 floppy drives, but
the floppies sitting in the 5 1/4 drive for the bridgecards have no protection
at all. At least the 3.5 floppy (when not inserted) are enclosed and protected,
albiet dusty.

> I am seriously considering reversing the fan on my 2000 the next time I 
> open it up.

	Last time I tore my A2000 apart, I removed the mother board to install
the last 2 AT connectors on the PC bus. I cleaned the dust off everything,
since removal of the motherboard is about the only way to get at 
everything easily. 

	I also disassembled the power supply. It was caked full of dust, lint,
you name it. Kinda scary when you think about thermally insulating power
handling components. Im full up on buss slots and drives, so I am sucking
close to the maximum power available as it is.

	A real mess to say the least.

	Here is what I will do during my next surgical operation.
        1) Reverse the fan.
		2) Rubber isolation mounting for the fan to reduce fan noise
		   amplified by the sheet metal case and cover.
        3) Last but not least, put a removable and servicable filter
           on the input to the fan.

    It may be debatable as to the good or bad of reversing the fan, but
I "feel" that the airflow internally is too "smooth" because of the fan
sucking, as opposed to the more violent blowing into the box, the 
turbulance generated from colliding and avoiding blocking passages.

	The reason I'm making this point is, I have many heat generating 
PC bus periphal cards on the far side, away from the fan, and they are
quite warm. In my opinion, the A2000 has a "hot spot" here. I honestly
don't see how reversal could be worse as far as component cooling is
concerned, but one thing is certain: My floppy drives will thank me!

    Anybody know of a good way to clean the floppy drives? I've thought
of "blasting" them with compressed air, but my mind sees images of
drive heads and whatever, flying out the other end.

	Of course, I don't have any wind tunnel data to back these opinions,
so take what I say here with a grain of salt.

	Im tired of the dust, clumps of hair, and lint all mixed together
blocking every concievable opening going into the A2000, and there many. 

	It's a pain to clean, and in my case, I have to do it often.
-- 
Harald Milne                   RISCy business	       uunet!ccicpg!boink!harald