Man... keep that fan blowing, and hard. If the fan is making machanical
noise, replace it. If you're not brave enough to slice the "warranty
void if removed... no user servicable parts inside..." sticker on the
PS, replace the entire power supply. If the noice is coming from the air
movement, make sure there's no restrictions (like extra cables hanging
behind your case) that are restricting airflow.
If the noice really bugs you, heck, just clip the leads to the fan, let
your system cook. You may or may not see premature death of your CPU and
hard drives as a result of the increased heat. If you're running the
machine at home, and plan to upgrade again in a year, you may be fine,
and may not care. If the machine is important to you, you should be
happy with the noise (assiming it's wind noise, not bearing noise),
since that means your machine is running happily along.
As for PWM modulation of a fan... PWM is more often used for things like
small DC motors in electromechanical systems... the print head in your
desktop inkjet is probably driven by a PWM-contolled motor, since it
needs precise controll over positioning, and needs to start, stop, and
change position rapidly. It doesn't sound very appropriate for a fan,
which is either on, off, or possibly running at a reduced speed. There's
probably a few EEs with motor-controller experience out there who could
say more...
--Rich
Joost Kooij wrote:
>
> On Thu, Jul 12, 2001 at 09:18:21AM +0200, thomas wrote:
> >
> > > So my idea is: I open the power supply, flip the fan so that it blows
> > > cool air from outside into the case, voila, much less noise. Is this a
> > > good idea or rather stupid?
> >
> > bad idea. you will move all the hot air in the case. if your man enough
> > take you PSU apart and mod your fans to 7V, that will make it almost
> > unhearable!
>
> IIRC you need to switch the fan on and off in rapid succession,
> it's called pulse width modulation. Presumably, it's better for
> the electronics inside the fan.
>
> Cheers,
>
--
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Rich Puhek
ETN Systems Inc.
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