On Sun, 20 Jul 2008 16:25:55 -0700, "David Farber"
wrote:

I'm servicing a Dell Dimension 4600 which is shutting down after about 5
minutes.

Look for bulging and leaking electrolytic capacitors around the CPU
area.
http://www.badcaps.net

The next time the PC boots, it gives a warning that the previous
time it shut down was due to a thermal problem. That led me to notice
that the CPU fan wasn't turning. The part number of the fan is 9G180. Inside
the fan housing is a small two terminal device. It measures about 6.3k ohms.
Is this an open fusible link,
a thermistor, or something else?

It's a thermistor. It controls the fan speed and exhaust air temp.

There are quite a few replacment fans available on eBay. For example:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200240190933
$14 with shroud. Replace.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558