"~misfit~" <misfit61nz@hooya.com.au> schreef in bericht
news:4871ee16$1@news2.actrix.gen.nz...
> Somewhere on teh intarweb "Mike Walsh" typed:
>> ~misfit~ wrote:
>>>
>>> Somewhere on teh intarweb "Paul" typed:
>>>
>>> [snip]
>>>
>>>> 4) The drive has a breather hole and particulate filter, and
>>>> on the outside of the drive, the label will say "don't cover
>>>> this hole". The breather equalizes the atmospheric pressure,
>>>> so that the air pressure inside the drive, is the same as the
>>>> atmosphere. The filter on the breather hole removes dust
>>>> particles, and has some resistance to moisture. But corrosive
>>>> gas could get through.
>>>
>>> And/or moisture.
>>>
>>> Unless the drive is stored in a temperature-controlled environment
>>> everytime it heats up or cools down (i.e. every day) there is going
>>> to be air movement through that tiny breather hole. Most air is
>>> moist. Condesation inside the drive in storage isn't a maybe, it's a
>>> 'for sure'. (Running drives create heat which largely solves the
>>> condensation problem and then, due to air expanion, drives the
>>> moisture out.)
>>
>> Condensation will not occur unless the relative humidity reaches
>> 100%.
>
> Really?
>
> "Water vapor will only condense onto another surface when the temperature
> of that surface is cooler than the temperature of the water vapor."
>
> http://en.wikipedia.org/wiki/Condensation
>
>> That rarely happens in a building with heat and air
>> conditioning.
>
> My home doesn't have either. This room temp was 11°C this morning when I
> was reading newsgroups. In summer it can reach 38° or so. Summer day/night
> fluctuations are fairly significant. Enough to 'pump' a fair bit of air in
> and out of a casing.
>
>> The amount of air going through the breather hole
>> during daily temperature changes is insignificant compared to the
>> amount of air that goes through during during normal use when the
>> drive is powered on and off.
>
> Maybe so but during 'normal use' the drive is producing heat which helps
> prevent any moisture from condensing.
>
> TTFN,
> --
> Shaun.
>
> DISCLAIMER: If you find a posting or message from me
> offensive, inappropriate, or disruptive, please ignore it.
> If you don't know how to ignore a posting, complain to
> me and I will be only too happy to demonstrate... ;-)
>

Thanks guys, much to read, but the end of the story:
it could have been everyting. :)

Thanks!
Marcel