T42 fan stuck on one speed

[b.jumbo]

greetings all,

i'm having problems with a fan on my t42 that won't speed up to bring down rising temperatures under sustained cpu load. it's stuck around 2600-2700rpm and it simply lets the temperature go up and up.

the problem seemed to start after running cpu intensive activities (ripping mp3s) on a hot summer day here recently. temperatures might have gotten away that time, not sure how high but maybe 80-100 deg. celcius. before, the fan would kick into a higher gear when the temperatures got too high. now, the fan stays at around 2600rpm and allows the temperature to keep climbing.

btw. i'm running ubuntu linux 8.04, and the latest bios (ver. 3.23).

i've tried turning up the fan using fan control software, and also by controlling the fan more directly using the thinkpad-acpi (see thinkwiki.com on "how to control fan speed"). neither has worked - although from reading the status of the fan the settings do seem to have been appied. the fan can be turned off, but any other setting only results in one fan speed. the fan does start off in the off position when the computer is cold, and turns on when it warms up. but, as i said, won't go beyond 2700rpm even as temperatures go beyond 70 and 80deg celcius..

cpu temperatures seem to be reported accurately.

i've opened up the machine and checked that it wasn't clogged with dust.

right now i'm suspecting that it's a hardware issue. could it be the fan unit? the motherboard? could something have been burnt out on that hot day where temperatures got too high?

if anyone could shed any light on this it would be much appreciated. thanks!

[fasterbybike]

Remove the fan following the procedure in the Hardware Maintenance Manual. Check the fan spins freely. If not, then replace it or dismantle and lube the spindle with a small smear of oil.

[Tim M]

I've noticed a similar issue with my machine; the fan is either off or spinning at ~2800 rpm according to NHC. Upgrading the motherboard and cleaning the fan have had no effect. System temperatures are fine, however (usually at 45-55 C for GPU and CPU with a maximum of 70 C CPU / 90 C GPU under sustained maximal load).

[b.jumbo]

... Check the fan spins freely. If not, then replace it or dismantle and lube the spindle with a small smear of oil.

as i said i've opened it up and cleaned out the bit of dust that was there. i could spin the fan with my finger and it seems free. if it was blocked i don't think it would turn on and off or spin at 2600rpm with such consistency.

I've noticed a similar issue with my machine...

bummer that the motherboard replacement didn't work. ..maybe it's the fan unit?

interesting that the cpu temperature maxes out at 70 c.. maybe it's the difference of 100-200rpm with my machine that keeps the temp lower..

so, do i understand you correctly, you've also tried to control the fan more directly but to no avail?