Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!husc6!rutgers!att!icus!limbic!gil
From: gil@limbic.UUCP (Gil Kloepfer Jr.)
Newsgroups: comp.sys.att
Subject: Re: Fan Recommendation
Summary: 2 fans -- not a good idea
Message-ID: <485@limbic.UUCP>
Date: 29 Apr 89 16:53:14 GMT
References: <1567@jhunix.HCF.JHU.EDU>
Reply-To: gil@limbic.UUCP (Gil Kloepfer Jr.)
Followup-To: comp.sys.att,unix-pc.general
Organization: ICUS Software Systems, Islip, NY
Lines: 32

In article <1567@jhunix.HCF.JHU.EDU> ins_anmy@jhunix (Norman Yarvin) writes:
>When I was shopping around for fans, I was told to look for a ball bearing
>AC fan, as those were the most reliable.  The fans I ended up with (yes, I
>put two of them in -- and am wondering whether to pull one out) were Pamotor
>model 8506D.  These are 110V AC fans with a rating of 36 cfm.  They were a
>bit thicker than the existing fan, so the grate on the inner side of the
>fans could not be replaced: any dangling wires inside the case should be
>tied down (existing wires are all tied down).
>					Norman Yarvin
>		(seismo!umcp-cs | allegra!hopkins) !jhunix!ins_anmy

I agree with Norman that one should replace their DC fans in the 3B1 with
an AC fan *before* the fan fails -- ie. as soon as possible.  Unfortunately
the fan is a necessity for the machine to stay alive.

One thing -- although it may seem like a good idea, keeping 2 fans going is
unnecessary and not a good idea.  First problem is that it tries to suck more
air through the case than it was designed for -- thus pulling lots of dust
through the floppy drive (and could damage the drive, if not make it unusable
until cleaned).  Second, there is really nothing on the left side (viewing
the machine from the front) that needs to be cooled.  One fan is plenty
for cooling -- even with 3 expansion boards in the machine.

One other side benefit of an AC fan is that they usually get *very* noisy
before they actually fail.  If your fan is constantly making a rattling
noise (an indication that the bearings are failing), the fan is about to
break and should be replaced.

------
| Gil Kloepfer, Jr.
| ICUS Software Systems/Bowne Management Systems (depending on where I am)
| {decuac,boulder,talcott,sbcs}!icus!limbic!gil   or    gil@icus.islp.ny.us