On Wed, Aug 13, 2008 at 05:31:37PM -0300, Henrique de Moraes Holschuh wrote:
quoted text
> > know the fans have a tendency to go bad within 12-18 months, and so
> > the CPU heat sink and fan unit needs to be replaced perdiocially.
> > What does /proc/acpi/ibm/fan report? 
> 
> ThinkPad fans have a overdesign range of about 2x, they almost never stop
> because they're too old.  Clogged in dirt, on the other hand... a clogged
> fan often spins FASTER and cools less.
> 
> Want to see how much your fan has as far as a safety margin goes? use
> thinkpad-acpi to measure RPMs in level 7 and also when you switch PWM off
> (i.e. set it to 100% duty cycle).  Mine gets faster by 1500RPM or so that
> reflects the extra torque the EC can apply to get the fan to run at the
> speed it wants it to.

Hmm, maybe I've just had bad luck, or I live in a very dusty
environment (four cats, including two longhairs in perma-shed mode,
will do that to any house), but I've had at least 3 fan failures in
the past 5-6 years where the fan stopped entirely, and had to be
replaced.  When I took it out, it was quite dirty, but the way it spun
why I tried moving the fan blades with my finger, it felt just like
the failure modes I've had with standard power supply fans that have
gone bad due to old age.

       	    	      	       	      - Ted

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