Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!indri!aplcen!jhunix!ins_anmy
From: ins_anmy@jhunix (Norman Yarvin)
Newsgroups: comp.sys.att
Subject: Fan Recommendation
Message-ID: <1567@jhunix.HCF.JHU.EDU>
Date: 25 Apr 89 03:21:53 GMT
Sender: ins_anmy@jhunix.HCF.JHU.EDU
Reply-To: ins_anmy@jhunix (Norman Yarvin)
Organization: JHU
Lines: 50

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).

The difference in quality between the new and old fans is apparent: the new
fans are all metal construction and weigh about twice as much as the old;
they take about a minute and a half (in open air) to spin down after power is
removed (the old ones stop very quickly).  The two fans in my machine are
close enough in frequency that they put out an audible beat (i.e. the sounds
go in and out of phase).  I have been running my system fairly continuously
for about 9 months with these fans.

These fans were more expensive ($26/fan) than Radio Shack's AC fans, but
they should be worth it.  I got my pair from a local distributor (who will
probably ship orders COD from the looks of the invoice I have next to me):

	Almo Electronics
	8309B Sherwick Court
	Jessup, Md 20794-9632
	(301) 953-2566

For those just tuning in, the reasons to replace the fan in your Unix PC are
the following:

	1) The existing fans are very unreliable, and if they fail, your
	machine will literally melt.

	2) The machine, as distributed, runs very hot; the air coming out of
	my machine is much cooler than that coming out of stock 3b1s (I did
	a side-by-side comparison).

	3) By moving from a DC fan to an AC fan, you reduce the load on the
	power supply.

There is only one disadvantage: your machine will run more loudly.  I have
accepted this as a necessary consequence of having more airflow.

Of course, I accept no responsibility for anything you do to your machine
and make no guarantees of the correctness of the information above (what
little there was of it)

					Norman Yarvin
		(seismo!umcp-cs | allegra!hopkins) !jhunix!ins_anmy

  "I can't really represent the size of the sun on the blackboard,
   but this should give you a good idea."