What is purpose of wire mesh in Dell laptop charger cord?

[Mycroft668]

What is the purpose of the wire mesh and is the charger still usable?

Dell laptop charger. The cord from the charger to the wall plug is
fine. Off the other end of the charger which leads to the laptop, the
rubber reinforcer/grommet is broken all the way around at the charger
end. The internal wires and insulation around them are intact, but the
wire mesh that surrounds those wires and their insulation is
completely separated so that there is no connection between the mesh
at the charger and and the mesh under the reinforcer grommet. There is
no damage to the insulation or internal wires, just the wire mesh
between the internal wire insulation and the rubber grommet.

In other words, there are the innermost wires which are surrounded by
the wire insulation. This, in turn, is surrounded by a wire mesh. The
rubber grommet then surrounds all of that. The grommet is broken all
the way around as is the mesh. (The mesh is separated completely.) I
want to know if the wire mesh is part of the connection or if it is
just for strength and protection and to reduce radio interference. I
can't tell by the thickness of the cord if the mesh continues past the
thicker, reinforcing rubber grommet.

Thanks for your opinions and help on this.

Mike

[Jeff Liebermann]

On Tue, 28 Feb 2012 08:57:36 -0800 (PST), Mycroft668
<Mycr...@yahoo.com> wrote:

>What is the purpose of the wire mesh and is the charger still usable?

Shielding to help the charger pass FCC Part 15 radiation tests. The
shielding keeps the RF inside the charger. Since you didn't bother to
supply the model number of the charger, I can only guess the reset.
Some Dell chargers use the shield as the ground wires (negative). If
it is a coaxial arrangement and there is a foil shield, the braid is
also used to hold the foil in place so that it doesn't tear when the
cable is bent.

If you broke the cable at the connector, you'll need to re-establish
continuity at the "wire mesh", also known as the braid or shield. If
there's a gap missing, wrap it in copper tape, and solder both ends.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Mycroft668]

On Feb 28, 3:07 pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Tue, 28 Feb 2012 08:57:36 -0800 (PST), Mycroft668
>

> <Mycrof...@yahoo.com> wrote:
> >What is the purpose of the wire mesh and is the charger still usable?
>
> Shielding to help the charger pass FCC Part 15 radiation tests.  The
> shielding keeps the RF inside the charger.  Since you didn't bother to
> supply the model number of the charger, I can only guess the reset.
> Some Dell chargers use the shield as the ground wires (negative).  If
> it is a coaxial arrangement and there is a foil shield, the braid is
> also used to hold the foil in place so that it doesn't tear when the
> cable is bent.
>
> If you broke the cable at the connector, you'll need to re-establish
> continuity at the "wire mesh", also known as the braid or shield.  If
> there's a gap missing, wrap it in copper tape, and solder both ends.
>
> --
> Jeff Liebermann     je...@cruzio.com
> 150 Felker St #D    http://www.LearnByDestroying.com

> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann     AE6KS    831-336-2558

Thank you for the reply. I'm sorry I didn't give the model number of
the charger - I didn't know it mattered. Here are all the numbers
Model is Dell LA65NS0-00 and it also says PA-12 family. DP/N is
DF263 other numbers shown are PA-1650-06D3

The braid is broken too close to where it enters the charger for me to
be able to work with unless I open the charger and try to do some
major work from the inside but there are no obvious screws so that
wouldn't be worth it since I don't want to break the plastic case.

The true question is whether the charger is still usable. Would I be
able to tell with a multi tester? Output is 19.5V DC but I measure
much less (I think it was around 3V). Would it hurt to just plug into
the laptop and see if it seems to work ok? If the charging light goes
on, would this mean it is working? i.e., would this break in the braid
be a works 100% or doesn't work at all type of thing?

Thanks again. It's for a friend who doesn't have a spare cent to buy a
replacement unless it is absolutely necessary.

Mike

[hrho...@att.net]

On Feb 28, 2:07 pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Tue, 28 Feb 2012 08:57:36 -0800 (PST), Mycroft668
>

> <Mycrof...@yahoo.com> wrote:
> >What is the purpose of the wire mesh and is the charger still usable?
>
> Shielding to help the charger pass FCC Part 15 radiation tests.  The
> shielding keeps the RF inside the charger.  Since you didn't bother to
> supply the model number of the charger, I can only guess the reset.
> Some Dell chargers use the shield as the ground wires (negative).  If
> it is a coaxial arrangement and there is a foil shield, the braid is
> also used to hold the foil in place so that it doesn't tear when the
> cable is bent.
>
> If you broke the cable at the connector, you'll need to re-establish
> continuity at the "wire mesh", also known as the braid or shield.  If
> there's a gap missing, wrap it in copper tape, and solder both ends.
>
> --
> Jeff Liebermann     je...@cruzio.com
> 150 Felker St #D    http://www.LearnByDestroying.com

> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann     AE6KS    831-336-2558

Or just epoxy the heck out of what you have and don't complain if
there's some interference to any of your other local electronics

[Mycroft668]

On Feb 28, 3:07 pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Tue, 28 Feb 2012 08:57:36 -0800 (PST), Mycroft668
>

> <Mycrof...@yahoo.com> wrote:
> >What is the purpose of the wire mesh and is the charger still usable?
>
> Shielding to help the charger pass FCC Part 15 radiation tests.  The
> shielding keeps the RF inside the charger.  Since you didn't bother to
> supply the model number of the charger, I can only guess the reset.
> Some Dell chargers use the shield as the ground wires (negative).  If
> it is a coaxial arrangement and there is a foil shield, the braid is
> also used to hold the foil in place so that it doesn't tear when the
> cable is bent.
>
> If you broke the cable at the connector, you'll need to re-establish
> continuity at the "wire mesh", also known as the braid or shield.  If
> there's a gap missing, wrap it in copper tape, and solder both ends.
>
> --
> Jeff Liebermann     je...@cruzio.com
> 150 Felker St #D    http://www.LearnByDestroying.com

> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann     AE6KS    831-336-2558

[Ian Field]

"Mycroft668" <Mycr...@yahoo.com> wrote in message
news:63f821aa-3036-43e7...@k29g2000yqc.googlegroups.com...

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Of some significance is whether the braid screen encloses 2 or 3 insulated
wires, if its 3 the PSU has an earth if not its most likely "double
insulated" as they'd unlikely rely on the mechanical construction as the
sole means of earthing the appliance.

Check continuity from the exposed braid to the earth pin, if its connected
fine, if not your options would be limited by whether the plug is molded or
dismantleable.

If all it does is contain RF radiation from the mains lead, it shouldn't
have any bearing on the functionality of the PSU, but as someone else
mentioned it could interfere with other equipment - for example you may not
be able to listen to FM radio while charging the laptop.

[Jeff Liebermann]

On Tue, 28 Feb 2012 13:36:11 -0800 (PST), Mycroft668
<Mycr...@yahoo.com> wrote:


>Thank you for the reply. I'm sorry I didn't give the model number of
>the charger - I didn't know it mattered. Here are all the numbers
>Model is Dell LA65NS0-00 and it also says PA-12 family. DP/N is
>DF263 other numbers shown are PA-1650-06D3

<https://s3.amazonaws.com/UETechPics/HN662-1.JPG>
65 watt. 19v.

>The braid is broken too close to where it enters the charger for me to
>be able to work with unless I open the charger and try to do some
>major work from the inside but there are no obvious screws so that
>wouldn't be worth it since I don't want to break the plastic case.

It's quite easy to crack the case without damage. Place in a PADDED
bench vice and squeeze along the case crack lengthwise. You should
hear a crack when the glue line breaks.

>The true question is whether the charger is still usable. Would I be
>able to tell with a multi tester?

Yes, partially. It should output 19v.

>Output is 19.5V DC but I measure
>much less (I think it was around 3V).

You're measuring to the wrong connections. Look at the connector.
There's a center pin, which is the data pin used by the power
controller in the laptop to argue with the power supply over whether
it's capable of charging the battery, or just powering the laptop. It
is NOT one of the power wires. If you look inside the connector,
you'll see that the inside of the barrel is tin clad. That's the
positive contact. The negative contact is the outside of the barrel.

>Would it hurt to just plug into
>the laptop and see if it seems to work ok?

Hurt whom? I feel no pain when I do that.

>If the charging light goes
>on, would this mean it is working?

Yes. That means that the PS and laptop power controller have had
their discussion and agreed that everything is just fine.

>i.e., would this break in the braid
>be a works 100% or doesn't work at all type of thing?

The break in the braid is the negative PS wire. Nothing is going to
happen until that is fixed.

>Thanks again. It's for a friend who doesn't have a spare cent to buy a
>replacement unless it is absolutely necessary.

I think you'll find it both better and easier to buy a replacement
charger.
<http://www.ebay.com/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=PA-1650-06D3>
$8.


>Mike
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS

[Mycroft668]

> Of some significance is whether the braid screen encloses 2 or 3 insulated
> wires, if its 3 the PSU has an earth if not its most likely "double
> insulated" as they'd unlikely rely on the mechanical construction as the
> sole means of earthing the appliance.
>
> Check continuity from the exposed braid to the earth pin, if its connected
> fine, if not your options would be limited by whether the plug is molded or
> dismantleable.

Thanks for that, but I didn't understand the reference to the earth
pin. It probably doesn't matter because, if you read the OP, you will
see all the wires are enclosed together in their own insulation so I
don't know how many there are.

But thank you all for taking the time to help me. I think I have the
answers now which I will post here perhaps to help someone else
sometime.

I have obtained the laptop and the charge light does not go on unless
I manually connect the severed braid with a piece of wire. Then the
charge light does go on. I am assuming the laptop is now charging
normally since I don't, at the moment, have the password so can't log
on and see the battery status indicator.

I cut away the rest of the rubber casing (about 1/4 inch) at the
charger end to expose as much of the braid as possible and stripped
some insulation off the cord. It's not so much a braid or mesh... more
like many strands of silver wire running the length of the cord and
all around it. I'm guessing it has to do with the RF stuff. Anyway, I
soldered a length of wire to both sides to connect the two and taped
it up. No flickers when jiggling so it seems like a workable repair.

I would have bet against that braid being part of the electrical
connection (and lost) but that's how we learn stuff.

Thanks again.
Mike

[who where]

On the PA-6 family there are two insulated wires within the screen.
The screen IS the ground and is required for charging, period. It is
also the weak point in these chargers. although normally this
bending-fatigue takes place at the laptop end where there is a far
greater prospect of the cord/grommet junction experiencing frequent
and significant bending.

I have had this same experience with a PA-6 charger in the past. To
the question in your follow-up post - there was no damage caused here
by trying to charge with the return braid broken but as always YMMV.
If you do want to check it out, bridge the break and you'll see the
difference.

Generally you can pick up these chargers cheaply off fleabay.