[ltp] T41 fan broken?

[Nate]

I'm unsure whether my fan has been working properly for a while now 
because it just never seems to be on very fast. I'm running FC5, with 
ibm_acpi.

Today my fan mysteriously ramped up to what sounded like high speed for 
the first time in 6+ months. About 6 months ago I sent it to IBM with 
bad video memory and they replaced the main board (they said). At the 
time the fan sounded rattly and but still pushed a lot of air when it 
spooled up. Today the volume of air was not great however even though it 
was loud. I was not doing anything unusual at the time. I then read 
about ibm_acpi and wanted to see if I could get the fan to ramp up 
again. I started playing multiple videos and managed to get the temp up 
to around 85/86 degrees C, but the fan never changed speeds noticeably.

Below shows how quickly the cpu can cool down after I take the load off.

[root@blackbox ~]# cat /proc/acpi/ibm/thermal; date
temperatures:   85 50 34 65 36 -128 31 -128
Sun Aug 13 21:59:56 EDT 2006
[root@blackbox ~]# cat /proc/acpi/ibm/thermal; date
temperatures:   59 50 34 61 36 -128 31 -128
Sun Aug 13 22:00:43 EDT 2006

To gauge the effectiveness of the fan, I let the cpu get up to 89 C by 
turning off the fan and loading the cpu. I was afraid to let it go any 
higher so I turned the fan to max (which is hardly perceptible, I'd 
expect some significant noise) and the cpu temp went down to 86 and 
stays constant for minutes. Is there a maximum cpu temp before hardware 
protections shut the machine down or similar protection?

I still have 6 months of warranty left on the machine. I think I'll end 
up sending it in for a new fan, but I need the machine right now, so 
it'll have to wait.

Can anyone recognize these symptoms and can confirm this is unusual 
behavior and a hardware problem?

-Nathan