Re: Battery charging problem with connected ethernet
Hi all,
> In case that i have been connected to my intranet over ethernet the
> operation mode changes from AC mode to battery mode. It is not possible to
> work in AC mode with a ethernet connection.
This sounds suspiciously like a problem I had some time ago:
http://lists.debian.org/debian-laptop/2006/08/msg00103.html
I experienced the same problems as you -- wired ethernet did not work with
that particular AC adapter plugged on one particular network. If I changed
power supply, ran off batteries, or went to a different network, the wired
ethernet was fine.
I never did discover exactly what was going on here, but here are some things
that might help you that I did find in the course of investigating this
problem and a number of other laptop power supply-related problems we have
been having with instrumentation in our labs.
* the power supply in question was a non-genuine one. [0]
* laptop power supplies are pretty ugly in the electronic sense. They produce
amazing amounts of electrical noise in the 50-100kHz range that ends up
coming out in all sorts of places where it shouldn't. Non-genuine power
supplies are worse than genuine power supplies at this at this too. [1]
* even though the power supply may claim to produce a certain voltage and you
can measure that using a voltmeter, when you look more closely on an
oscilloscope, they tend have a ~0.5V sawtooth around the nominal voltage
(this sawtooth is the 100kHz noise)
* the "ground" from the power supply tends to float around a bit so you can
have a substantial difference between the "ground" of your laptop and
the "ground" of other powered devices that are plugged into it. This includes
powered usb devices and network cables.
Whether it was the under-voltage or the noise that stopped my ethernet
connection I am not sure, but I did find that could work around the problem
satisfactorily in two ways: 1) I changed the network kit at the other end of
that ethernet cable (it was a network card at the end of a cross-over cable)
or 2) I took that power supply elsewhere where I only use a wireless network
and got a different power supply for that location where I used the wired
network.
I hope that provides some inspiration to you (and suitable amusement for the
rest of the list!)
cheers
Stuart
[0] it was purchased from ebay... I should have known better... non-genuine
power supplies seem to cause many more problems than the save in cost.
[1] Looking at 4 genuine power supplies and 5 non-genuine ones that we had
available to us, we found significantly more noise coming from the
non-genuine power supplies to the point where a couple of non-genuine power
supplies for thinkpads just cannot be used any where near our instruments --
don't even plug them into the same wall socket!
--
Stuart Prescott www.nanoNANOnano.net
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