SMART fan won't shut off

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wooxuexue
Posts: 2
Joined: Fri Apr 28, 2006 11:14 pm

SMART fan won't shut off

Post by wooxuexue » Fri Apr 28, 2006 11:27 pm

Hi,

My system is:

Case: Antec P150
MB: ECS nFORCE3-A
CPU: Sempron 2800+
FAN: AMD fan included in CPU box
OS: Win2000 SP4

I changed the BIOS to make the CPU fan run in SMART mode. When I boot up the machine, the CPU fan is shut off, and continued to be off well after the long Win2000 boot-up sequence (1~2 minutes), at which point the CPU is about 38C.

If I keep the machine idle, at some random point (about 5 minutes), the fan will start to spin, and will cool down the CPU to around 32C. But the fan never shuts off.

The only reliable way to shut off the fan is to suspend the machine and wake it up immediately. When the machine wakes up, the fan doesn't start. But after a few minutes it starts again and refuses to stop even when the CPU is cooled down to 32C again.

Any hints? Is there an OS driver that I am missing?

Jan Kivar
Friend of SPCR
Posts: 1310
Joined: Mon Apr 28, 2003 4:37 am
Location: Finland

Post by Jan Kivar » Sat Apr 29, 2006 2:34 am

Try to give a gentle spin to the fan blades when the fan is initially off. If it starts to spin, the motherboard doesn't supply enough voltage to start the fan at the lowest speed. When the temperature rises, the motherboard bumps up the fan voltage and the fan starts to spin. As the voltage is lowered to the minimum value again, it is enough to keep the fan spinning.

You could also try to stop the fan when the CPU has cooled down and see if it then stays off.

Cheers,

Jan

wooxuexue
Posts: 2
Joined: Fri Apr 28, 2006 11:14 pm

Post by wooxuexue » Sat Apr 29, 2006 9:32 am

I forgot to mention: when I turn on the computer, the CPU fan runs for a short while, and then it is shut off (presumably by the SMART logic), so I am pretty sure the MB gives it enough power to start up.

Also, if I change the BIOS to run the CPU fan "always on", then it will start immediately at boot up and stay on forever .....

Does anyone have experience with my MB: ECS nFORCE3-A? I bought it at Frys with the Sempron 2800+ for only $69 *both*. That was a good deal, but maybe there was a reason for it :-(

Firetech
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Location: Sydney, Australia
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Post by Firetech » Sat Apr 29, 2006 10:59 am

You need to adjust the temp settings in the BIOS if you want different temps. But the fan will continue to run once the system is up to temperature but slowly.
Have a look at this thread :)

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