[vdr] Re: Hardware falures

[Christian Berger <einStein@donau.de>]

Stefaan Coddé schrieb:
> 
> ----- Original Message -----
> From: "Christian Berger" <einStein@donau.de>
> To: <vdr@linuxtv.org>
> Sent: Tuesday, April 30, 2002 5:14 PM
> Subject: [vdr] Re: Hardware falures
> > I wonder why my Pentium 90 needs a fan, but my IBook doesn't need one
> > and doesn't even get warm. :)
> 
> Who says it definatly needs a fan? With everything : try to use something
> to transport the hotest surface which is usual small on size....to a much
> larger
> area.  If this area is big enough then natural convection will be enough to
> keep
> the temperature low enough. a computer case isn't built according to this
> principle
> and I wonder why the hell not?
> Case manufacturers sure didn't took the time for a thermal analysis on their
> product
> cause 99.9% of all cases would not pass that test.

Yes, computers just aren't designed well anymore. This started in about
the 70s. For example the Altair did have simple linear power supplies
(to get 20 amps). The Apple I had a modulator designed so badly, it was
able to distort TV-sets in a range of several hundred meters (according
to rumors)
Computer hardware just isn't designed that well. 
 
> I have no idea on the internal setup of an Ibook but it's prolly a
> combination with a
> low power CPU or somethimes called mobile CPU cause they are used alot in
> laptops
> in combination with a simple heat exchanger.
> This can be a pipe or a plate, in fact.. can have almost any form.
> Second.. how big is the harddisk? prolly a 2.5inch which make less noise and
> generta less heat
> too and power supply... internal or external and how heavy?

Well the external power supply is 45 Watts. Yes it's a 2.5" HD. but I
don't think it'S a special "low-power" processor, it's just a standard
G3 with a piece of metalic foil (not even that large) on top.

> What I mean is : there are many places where it's possible to use less for
> cooling compared
> to a standard computer setup.
> 
> > > Tower PC's : too bad, all cards are mounted horizontally which is VERY
> bad
> > > for heat dissipation.
> >
> > Well it helps a bit to turn the case upside-down and install a fan on
> > one side.
> 
> Indeed, such things do help a bit but You add a fan again = extra unwanted
> noise.

Well the noise inside the 19" case is no problem for me. And that fan is
"ultra-silent" almoust as silent as a harddisk.
 
> > Well my problem is how to get out the heat out of the 19 inch rack. I
> > currently have a 25 Watts Pabst fan installed getting the air directly
> > from outside.
> 
> Phew, 25Watts...that's a heavy fan. A fan makes twho different kind of noise
> levels:
> 
> 1) typical humming sound cause by the unstability of the blades.  If used in
> a light cheapo
> case then those vibrations are amplified by the case.

Yes in my case they are heavy metal blades so minimal differences can do
a lot.
 
> 2) air noise : the air hits alot during it's travel. This generates the
> typical 'whoosh' sound.

Yes this is found in the "air-inlet hose".

Both reasons are why I usually don't turn it on, unless maybe even in
summer during the day when I don't sleep.
 
> Try this: remove the cover of the chassis and turn the computer on.
>             Measure the temperature and if all stays at a reasonable level
> then you can throw
>             every system fan away and even think on a noiseless system.
>             btw, it's expensive tho. There not soo much difference in price
> between a futureclient
>             and my media box.... but my media box supports more.

Well one thing I've been thinking of is using a chimney. That way the
warm air could circulate up. This could also move the fan to a position
far away from whereever I am.


One thing I definitely would _not_ recommend is oiling fans. It often
makes things worse.

Servus
  Casandro