Thanks Terry, you know the first thing I was going to do when I realized it
wasn't a grounded plug is try reversing it, but I never got around to it,
but I will the next time at the boat.

As I said, this is more a nuisance than a problem. I don't consider it a
safety issue and thus I'm not planning on putting a lot of effort into
solving it--bigger issues to focus on.

John

"Terry Spragg" wrote in message
...
JohnHH wrote:
Another lie, the power brick is only two wire and the prongs aren't
polarized. Funny how different things look when you look at them. Maybe
it was the Dell that had the three wire plug.

So, progress, eh?

It's easier to see when you use your eyes. It's easier to think when you
don't put garbage into your brain.

So, with a 2 wire cableset, unpolarised, did you try it plugged in both
ways?

Does it do "it" both ways? Is there a great bloody gash and bare wires
hanging out the cableset? Covered with black tape? "Sealed up" with smunge
from years of handling? Smunge is that black goo that costs so much when
spread thinly, hundreds of coats, on "antique" furniture. It comes from
human hands and exhalations, sometimes called "patina."

If only one way, there is probably a .01 uf "decoupling" capacitor from
charger "chassis" ground to one side of the supply, depending on which way
it's plugged in. It will be leaky, or possibly open. Replace it with a
good one. Don't ask how I know, I've been told I get too technical. The
device might have internal transformer caused eddy currents or switching
transients capable of tunnelling through the insulation into the ether.

Otherwise, there ain't no way this thing can pop a gfci unless there is
leakage through the electrocutee. That's you. Try it again with rubber
boots on, and rubber gloves. If that solves the problem look for
something like an almost dried puddle of puke somewhere near where your
hand contacts the case or perhaps a salty damp berth cushion and sweaty
underpants, all too close to the wire mesh ssb "ground" plane or something
really strange.

Reroute the power cableset, away from where it usually is. Try again. Does
it happen at only one one outlet / location?

Laugh if you want, but this is the real world talking, and truth is
stranger than friction, as they try to say...

Does this thing have an antistatic plastic case, possibly conductive
enough to allow this leakage? Paint it with a good insulating varnish, or
keep it in a plastic baggie.

Buy a different brand of gfci, maybe a cheaper one will serve better.

Terry K


"Larry" wrote in message
...

w_tom wrote in :


First, to have a common mode noise (leakage), the computer
must have separate incoming and outgoing electrical paths.
Incoming is AC electric. What is the outgoing path?

The ground in the computer is hooked to the ground in the NMEA bus, the
printer through the printer cable, the computer's own troublesome
charger.
Because of any NMEA connections, it's also connected to that AC battery
charger under the quarterberth, which is also hooked to AC ground.

How many paths does it need??


Second, leakage through a resistance is rare. Leakage
occurs more often through reactive devices. That means the
ohm meter will not measure leakage through components whose
conductivity increases with frequency and voltage. IOW these
leaks would appear as high resistance (notice I did not say
impedance) to the meter.

This troublesome computer has a 3-prong grounded power plug, so we may
assume it also has in input double pi line filter, or at least some disc
ceramics in the .01 to .05 uF range between "hot" and neutral and ground.
The ac current differential caused by the input filter's capacitors is
more
than enough to cause trips, which is why I wanted him to first plug the
computer into a ground buster to eliminate the connection between the
computer power supply ground and the boat AC ground to isolate this type
of
tripping. If the ground buster fixes the problem, he merely leaves it
plugged into the ground buster and goes about his business, occasionally
getting a tingle from the ground on the RS-232C shell, maybe. He'd be
fine.

Then, I was going to have him measure the voltage between the unconnected
ground pin and boat ground to see how hot it was. You can imagine the
$24
switching power supply of the bargain laptop has nothing but the finest,
mil-spec line filter parts....totaling, probably, 10 cents, tops....


Third, all appliances have leakage. GFCI trip is not just
from one device. Sometimes it is leakage from numerous devices
combined. And yet the meter would test every device and see
no leakage from any of them.

Maybe nothing else is plugged into this OUTLET GFI. It could serve more
than one outlet from its internal terminals, though. The GFI outlet in
my
bathroom services the AC outlet on the side of my house, too.


Notice - without numbers then one can only speculate.

Everything we do on this newsgroup is speculation...an exchange of
guesses
and ideas that usually come up with a solution or prod the asking party
into taking a different path to the solution than the one he was
taking....