lap top fans

[joko]

how can you tell if they are broken?

mine only come on now and again - i think?? they are not on now

how often shouls they come on or should it be continuous?

thanks

[Beswad]

Mine use to come on now and again, but not anymore.

I think there's a heat sensor or there's a micro-processor switches the fan on when there are more programs running.

[Simeon]

As Beswad say's they are controlled by the proccessors temperature. The reason they don't run all the time is because they drain battery power so only swith on when they need to.