CPU temperature Thinkpad R61

[Fernando Cassia]

2009/10/16 Christoph Höger <choeger at cs.tu-berlin.de>:
> Am Freitag, den 16.10.2009, 07:18 -0300 schrieb Fernando Cassia:
>> 2009/10/16 Christoph Höger <choeger at cs.tu-berlin.de>:
>> > Am Donnerstag, den 15.10.2009, 17:34 -0500 schrieb Mikkel:
>> >> Christoph Höger wrote:
>> >> > Hi,
>> >> >
>> >> > I just wondered why my fan always runs after a while. After closing
>> >> > firefox (which took 50% cpu along with X) I now have a load of roughly
>> >> > 0.06 - barely nothing computed at all. Both cores are in the lowest
>> >> > config and yet my cpu temperature goes from 42°C to 47°C in roughly 2
>> >> > minutes (and back by fan activity).
>> >> >
>> >> > I would understand this if there was some load, but what causes my CPU
>> >> > to heat if it does nothing? Design failure? Has anybody seen such a
>> >> > thing?
>> >> >
>> >> > regards
>> >> >
>> >> > Christoph
>> >> >
>> >> When was the last time you cleaned the dust out? Also are the air
>> >> vents on the laptop clear when in use?
>> >
>> > I am aware of that dust thing (I am going to give a compressor a try),
>> > but the heat goes up when the notebook and the fan is idle. That should
>> > not have anything to do with dust, right?
>>
>> When computers are idle (but active, I mean NOT hibernating or
>> suspended) it doesn´t mean the CPU fan stops completely. Sometimes
>> those spin at very low rpm so you don´t "hear" it, but the fan IS
>> spinning, albeit at very slow speed.
>
> My fan-o-meter tells me it's at 0 RPM - that's what I'd call idling.
>
> Strange thing is: I think the controller of that fan is in "learning
> mode". In the early days, it used to prevent 50°+ at all cost, now it
> even sometimes does not run at 53°. Is that some kind of ageing?

It´s probably stuck in dust. The board is likely sending a low voltage
but the fan doesn´t yet "start" because of all the dust it´s got
around it.

The fan monitor shows the TRUE voltage revolutions (that´s why cpu
fans need 3 wires, two send voltage for it to spin and the other
reports back every spin of the motor-blades), not the voltage it´s
being sent to make it spin. (the board could be sending full voltage
to make it spin at max speed, at yet the cpu fan meter would show 0
rpm, if the fan is stuck in dirt or you placed your finger on top of
it to make it stop).

I guess you know what I mean... in other words: blow some compressed
air from a decent air compressor (as I said cans do not have equal
airflow power) into the cpu air exhaust vents at the back of your
lappy. If you hear the internal cooler hum (it´s likely spinning
backwards due to the reverse airflow), it means it´s working. After
3-4 seconds stop. Also move from side to side to cover all the
sections of the air exhaust vents.

You will likely get a nice cloud of dust expelled by the cooler... so
don´t do it near food or clean clothes... I always place the notebook
on a ceramic-cement-wood floor (never carpeted) while doing this
procedure. Makes cleaning up easier.

FC