> Jeez, strike my last response, I replied before reading all the details.
> You measured the AC Line voltage with the scope, and that made a spark?
>

Yes, i plug the scope in the main, switched on, self test passed ok, then
attach the probe to channel 1, the clip in the probe to one wire of ac line
(not shure if neutral or live), and the pin of the probe to the other wire
of ac..-> spark!.

i explain miself if the clip of the probe is connected with the earth of the
main, what i do is make a short between neutral o live to earth, across the
scope. what make me suspicius is i think that both terminal of the probe
(clip and pin) MUST be isolated from ANY lead of main (gnd, neutral and
live) -- but, David Duffy say "Yes, it's normal for the CRO probe to be
referenced to mains earth".

the project anyware is not battery powered, and is not isolated with a
transformer, but the above test was made without the project, only scope and
line.

Thanks.

RVP.

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