Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!swrinde!mips!smsc.sony.com!dce
From: dce@smsc.sony.com (David Elliott)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Mac II Fan
Message-ID: <1991May26.173013.3010@smsc.sony.com>
Date: 26 May 91 17:30:13 GMT
References: <2102@hpwala.wal.hp.com> <00949272.62C546C0@uclapp.physics.ucla.edu> <13583@dog.ee.lbl.gov>
Organization: Sony Microsystems Corp, San Jose, CA
Lines: 36

In article <13583@dog.ee.lbl.gov> osborn@ux1.lbl.gov (James R Osborn) writes:
>
>My friend has an original Mac II that he is soon going to
>be upgrading to a IIfx.  The power supply doesn't get any
>upgrade and his original fan (built in to the power supply)
>is very virulent and noisy!
>
>I suggested to him that we could purchase one of the Quiet
>SE fans and replace it.  Alternatively, I seem to remember
>something about adding in a resistor.

There are a number of alternatives, but you must be careful.

You can replace the fan with a quieter fan (such as an SE fan or the
Radio Shack fan), but a quieter fan usually means a reduced airflow.
This can result in damage to the power supply (I know about this
from firsthand experience -- over $200 in repair and shipping costs,
plus a lot of aggravation) unless special care is taken to keep
the unit away from excessive heat.  If the Mac is to be kept in an
office or a room that doesn't get too hot, it may be fine, but even
keeping it near a window can cause problems.

A better alternative is to get a fan controller, such as the Nova.
This consists of a thermostat and a circuit that causes the fan speed
to be a function of the temperature of the disk drive.  When the
machine is cool, the fan goes slower, thus making less noise.

I definitely recommend the latter over the former.  It's more
expensive, but the fact is that when the machine gets hot, the quieter
fan simply won't be able to cool the machine.

I always thought it would be a good idea for someone to invent a
temperature-sensitive fan card that fit in a NuBus slot.  It could be
placed where it would do the most good.  Heck, it could even be made to
sample temperature and humidity data and make it available on the bus
for programs to display.