[Techtalk] OT but I'm desperate.... Windows....!

[Meredydd Luff]

On Friday 18 October 2002 17:49, Maria Blackmore wrote:
> On Thu, 17 Oct 2002, Alvin Goats wrote:
> > This can still lead to a brown out type condition (before tripping
> > circuit breakers/blowing fueses).
>
> If the voltage drop caused by additional load on the same circuit is
> sufficient to cause problems, then I would suggest that the house wiring
> needs to be looked at in some depth.
Well, from the sound of it, that is indeed the case here :-P

> Mains voltage is very well regulated, and has a lot of oompf behind it to
> back it up.  The voltage drop across properly installed cables when
> addition load is applied should be pretty much negligible, and the voltage
> droop caused by the additional load should be easily corrected by
> regulating transformers after a short delay.
Yes, but you get dodgy stuff. My house is at the moment drastically 
underpowered - there's a noticeable drop in the brightness of the lightbulbs 
when you turn on the vacuum cleaner. This worries me, and not just for the 
health of my computers, but we're re-wiring it completely soon (which will be 
a welcome relief!).

As for the regulation of mains voltage - it's not just that it's heavily 
backed up. When you get a blackout, often it's not because the line you're 
feeding off has been severed, but rather that the national grid, for some 
reason or another (usually some power stations being down), can't supply 
enough power to keep the pd in an acceptable range. As a result, they 
completely shut off some areas rather than having a (far more damaging) 
universal brown-out.

> The time period that the mains voltage droops for doesn't matter anyway,
> since if the power supply is correctly regulating its output rails then it
> should have no effect, in fact a well designed power supply should be able
> to cope with no power coming into it at all for at least half a cycle of
> 50 Hz or 60 Hz, usually much more (the hold over time).
What about long-term? Within a few seconds (unless my knowledge of capacitors 
is way out), no extra charge will remain in the PSU, leading to it being 
unable to maintain a high enough pd.

One thing I would actually like would be a PSU that shuts itself off when 
this happens, rather than carrying on regardless...

> Power supplies
> should be able to cope over a range of voltages at least as far apart as
> 100 and 120 V or 220 and 240V.
Yes, but in badly wired houses it's possible to have significant deviation 
from those values.

>  I believe (though I'm probably wrong) that
> the acceptable range of voltages to find on a mains outlet in the USA is
> 90-130V, and in the UK/europe 210-250.  There is a percentage range
> defined, though I can't remember it off hand.
Those values sound right, but like you, I can't be sure =)

> As to the original problem, if it crashes every time you go to print, I
> would be rather suspicious.  Though the error pasted in another email
> would seem to suggest that windows is experiencing its equivalent of a
> kernel panic.
True - but every single kernel panic I've encountered resulted from hardware 
problems. On the other hand, I may be failing to take into account the sheer 
suckiness factor of some of our favourite monopoly's OSs...

Meredydd
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