any thoughts on why cooling fan keeps spinning up and down?

Robert L Cochran cochranb at speakeasy.net
Sun Jul 5 18:01:18 UTC 2009



On 07/05/2009 01:09 PM, john wendel wrote:
> On 07/05/2009 08:07 AM, Robert L Cochran wrote:
>> I think there is probably a physical cause. It gets too easy to blame
>> the operating system for physical device issues. The fan speed is
>> controlled in part by temperature sensors on the CPU and feedback from
>> the fan circuit itself. I think all the fan speed controls are managed
>> by motherboard parts, not by the operating system interacting with those
>> parts.
>>
>> Bob
>>
>>
>> On 07/04/2009 08:14 PM, Robert P. J. Day wrote:
>>> this is another problem i started having with the test version, and
>>> it's still happening now -- on my gateway laptop running fully-updated
>>> f11, the cooling fan keeps spinning up and down with about a 3-second
>>> period. it's really kind of annoying. occasionally, it will stop
>>> completely for a bit, then it starts oscillating all over again.
>>> thoughts?
>>>
>>> rday
>>> -- 
>
>
> Actually, modern notebooks (and probably most desktops) have their fan 
> controlled by the ACPI "thermal zone" driver - strictly software. 
> Saves the manufacturers a few cents on every motherboard.
>
> Regards,
>
> John

I'll look into this, thanks. On the other hand I've opened up enough 
system cases (including laptops) and cleaned more than enough dust 
bunnies or coffee spills to realize fan speeds can have very physical 
causes indeed. Don't think of the fan as "just" controlled by operating 
system software. There is usually a physical reason why the speed varies 
and that ought to be the first thing to check before suspecting the 
operating system.


Bob

>
>




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