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

[Leslie Satenstein]

Robert L Cochran wrote:
>
>
> 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
>
>>
>>
>
>
My thoughts are that it is a physical problem, possibly clogged 
processor cooling fins.  I once removed the heat sink (I DO NOT 
RECOMMEND THIS), and reapplied new heat-conducting goo and reseated the 
heatsink.