Re: Can dust inside an Apple IIgs catch fire?

[Michael J. Mahon <mjmahon@aol.com>]

Riccardo <rigreco.grc@gmail.com> wrote:
> Il giorno domenica 3 febbraio 2013 18:49:27 UTC+1, Michael J. Mahon ha scritto:
>> Riccardo <rigreco.grc@gmail.com> wrote:
>> 
>>> Hi Guy,
>> 
>>> 
>> 
>>> Take a look, this is the video experimental of "Tracking" electrical phenomena.
>> 
>>> 
>> 
>>> https://plus.google.com/photos/109178844091109135311/albums/5840661035299613937?authkey=CLfE973o5MiLLg
>> 
>>> 
>> 
>>> 
>> 
>>> Ric.
>> 
>> 
>> 
>> I've never seen evidence of this where the voltages are less than 1000
>> 
>> volts. Not likely in an Apple II system unless it spent a lot of time in a
>> 
>> conductive dust environment or salt spray!
>> 
>> 
>> 
>> -michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon
> 
> Is a possibility. This is a slow phenomenon, but it accelerates over time
> as a chain reaction, does not need a polluted environment overly. The
> small flow of current between the parties at different potential (on
> surface of dielectric) progressively alters the properties of the
> insulator (reduce the Resistance), so that the leakage current increases
> up to the final flash over. Is one of the minor causes of electrical fire
> in LV installations at 230V.
> 
> Ric.

230VAC has peak-to-peak voltage of over 320v, so I can easily imagine
that--particularly for narrow separations. 

I certainly agree that it's possible--just quite unlikely. Certainly it
would not happen anywhere but the line side of an Apple II. 

Opening the power supply and physically inspecting the few places where
line voltage is present would immediately reveal whether it was a factor in
the OP's case. 

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon