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Sheep · Jun 25, 2003, 04:22 AM

Hello,

This is for an 700Mhz iBook.
How does the fan get activated? Is there an internal themometer to measure the temperature and when it goes above a certain temp activates th efan? Or is it something extarnal that triggers it?
There has to be some kind of thermometer that measures at least something...
And if so is there an app to know the CPU temp of the iBook?
I tried all the temp apps of versiontracker and none work on the iBook.

Thanks!

ccsccs7 · Jun 30, 2003, 01:57 AM

The fan is completely autonomous. It comes on when the temperature threshold reaches a certain point (it will even run after putting the iBook to sleep!) It is not under the system's control.

As for not being able to tell the temperature, that is a feature that some chips (or whearabouts) have (a themometer) but some don't. My 600MHz iBook does have a themometer function)

stew · Jun 30, 2003, 08:03 AM

I don't htink it is completely autonomous. The fan of my iBook often starts spinning during reboots, right after the startup chime. I suppose there is a threshold somewhere in OpenFirmware that gets altered, or the CPU is switching power saving modes during a reboot. Anyhow, something must be different during the reboot than when running the OS, and I'm pretty sure it's not the hardware

ccsccs7 · Jun 30, 2003, 08:11 PM

Originally posted by stew:
I don't htink it is completely autonomous. The fan of my iBook often starts spinning during reboots, right after the startup chime. I suppose there is a threshold somewhere in OpenFirmware that gets altered, or the CPU is switching power saving modes during a reboot. Anyhow, something must be different during the reboot than when running the OS, and I'm pretty sure it's not the hardware

Are you sure that's not the hard drive? I've noticed that with Mac OS 9, the hard drive spins down during a reboot and then back up after the chime (as you mentioned)(or, perhaps if a CD was left in the drive...). Mac OS X doesn't spin down the hard drive (as a matter of fact, it almost never spins down the hard drive).

I've only had my fan come on a couple of times, and it was very loud. What iBook do you have? Perhaps there could be a difference.

stew · Jul 1, 2003, 02:41 AM

It's definately not the harddrive, it's a completely different sound. The fan of my 800 iBook is very loud, unfortunately.

Yes, there are differences between various iBook versions: I used to own a late 2001 600MHz iBook before and I never ever heard its fan. Earlier this year I got a 800MHz iBook and I hear the fan several times a day.