Thinkpads Forum

Hello,

the CPU on my "new" 240X gets quite warm, actually hot.
I turned it over and saw that the fan wasn't running.
So I suspected a problem with the fan.
According to the HMM, the fan should be tested with the "test fan" option on the diagnostics diskette. I downloaded the diagnostics diskette and ran the test. And see, the fan actually stopped, started and stopped again as diagnostics test indicated. Thus fan test "passed".
How come that the fan doesn't run while I'm working? Is there some kind of temperature control build into the motherboard (i.e. only starting the fan when temperature rises above a certain level?
If so, any idea how I could check if the temperature sensor works correct? The last thing I would like to happen is that I will burn the CPU.

Kind regards,

Erik Meussen
Thinkpad 365XD, A31, T40, 240X

I would think there is a sensor under the heatsink that tells the fan to do its thing. Since you ran the test which showed your fan is mechanically OK, I'd remove the fan assembly, clean off any (original?) heat transfer pase and apply a dab of artic silver. I'm sure you've already cleaned out any dust etc but if not, now's the time.
Assuming none of the above is really needed, sometimes you just get lucky in that moving things around somehow makes everything work as it should!
Tim S

Thanks for the answer Tim.
The 240X is as clean inside as when it left the factory.
However, I haven't removed the heatsink, so I will see if it helps re-installing it.

Kind regards,

Erik

Hello Tim,

I removed the heatsink. It was clean (as was the fan itself).
I followed your advice and now the fan starts for a short while (during the BIOS boot as the IBM logo is shown).
As soon as the IBM logo disappears, the fan stops.
After the 240X has been on for a while (about an hour) the fan starts to spin slowly now.

On the Lenovo website I read amongst the BIOS updates that in one of the latest BIOS revisions "thermal control of CPU" has been build in. Thus I guess the fan only starts at a certain temperature.

Kind regards,

Erik

That sounds like typical fan operation to me. As I said sometimes moving things around pays off, and sometimes not!
If you have a heavyweight, CPU intensive program of some kind, you might want run it and double check the fan operation.
Tim S

Hello Tim,

that's a good idea. I will see if I can install GIMP on it.
Some GIMP options are CPU intensive.
I'll let you now the results.

Kind regards,

Erik

CPUBurn is CPU intensive....

http://www.brothersoft.com/cpuburn-175964.html