Over-revving Fan!!

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Hi, the main fan on my motherboard for the first time in 3 years is
going crazy. it seems to be running at beyond max speed 24/7, it will
not kick down. the inside of the computer is virtually dust free and it
never has a workload on it more then one window of explorer, or possibly
a game of solitare. Im clueless as to why this has happened but im
hoping i can fix it. any ideas or thoughts are greatly appreciated!! Ty

Re: Over-revving Fan!!

xsilentchaos wrote:

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I'd first check the fan and temperature settings in the BIOS and any
Windows software that monitors those parameters.  Sometimes the
software is configured wrong and reads the wrong temperature sensor or
even one that doesn't exist.  And if you've made any hardware changes
inside the computer recently, it's possible that a hot spot has been
created where the temperature sensor is located.  A shorted sensor
will also cause a high temperature reading, but another possibility is
that the hardware driving the fan may have a shorted output
transistor, and that may cause the full 12V to be applied to the fan
all the time.

Re: Over-revving Fan!!

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When my computer (HP 3.07GHz P-4) would over-rev, I discovered that the heat
sink  under the processor fan would be mostly filled with lint-like
material.  I used a straightened paper clip to clean out (pick and blow)
material as possible (power off, of course).

This did the trick.  You might also investigate a free app named motherboard
monitor.  Reports processor temperatures.


Re: Over-revving Fan!!

On Fri, 23 May 2008 12:30:52 -0500, xsilentchaos

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Is it possible the fan is not spinning any faster, it just
seems to be because the bearing has worn out and thus it is
making more noise?

What is the "main fan"?  On the CPU heatsink or a
northbridge or??  Check temperature reports in the bios
and/or windows hardware monitoring software if you have

Check bios settings to see if there are any controls for
adjusting fan speed.  Perhaps you had some failure to post
or a bad battery in the board and the presets for fan
control were lost when default values were loaded?

Also check the  heatsink mounting lugs, just in case one has
broken or popped out.  

If all else fails, try clearing CMOS and finally buy a
different fan with a lower max RPM, wiring it direct to 12V
from another fan header or a psu plug if necessary... but
more details might help.

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