Bob Larter Inscribed thus:

N_Cook wrote:
Bob Larter wrote in message
...
N_Cook wrote:
rebel wrote in message
...
On Sun, 26 Apr 2009 17:20:19 -0700 (PDT), "Mr. INTJ"

wrote:
I'm trying to replace the plug on a Dell laptop A/C power
adapter.
From the specs online, the barrel connector's measurements a
Outer dia.: 6.5mm
Inner dia.: 4.4mm
Pin dia.: 0.7mm
Barrel length: 9.5mm
You've done well to find those specs.

This is almost the same as EIAJ-05, but with different center pin
diameter. My guess is that Dell chose a non-standard or otherwise
hard-
to-find size so that users would have to buy new adapters from
them...
I'd say that's a fairly safe bet. Of course, they'd argue that it
is
to
protect
against all sorts of random/inappropriate supplies being connected
to
your
Dell
product.

Anyway, I've looked on Mouser and Googled in general, but I can't
find this particular size.

Does anyone know what this connector is called, or a source for
weird sizes like this?
If you turn one up, do let the group know.

As an aside, the earlier (non-concentric) style were even more
proprietary - if
that's possible.

I could not even confirm , off the web, including the service
manual
from
support.dell , whether the centre pin of an Inspiron 7000 DC
connector
was +
or - relative to the ground.
With most laptops, it's quickest & easiest to simply use a meter to
see which contact in the socket is shorted to the chassis.

But that does not tell you the polarity.

Of course it does. I've never yet seen (out of many hundreds of
laptops) one in which the ground connection don't go to the chassis.
All you have to do is continuity-test between the SVGA shield (for
example) & the power socket.

I agree ! I've never seen one either.

After more than 1/2 hour
fruitlessly hunting the web, decided to hook up to a current limited
supply and monitor the voltage at the pins of the connector. If draws
current and voltage is high then the right way round. Incidently pin
positive wrt the ground/outer barrel for the Inspiron 7000. Perhaps
in the States you only have to state the volts and currents and just
a DC symbol at the socket, not the "C and dot" polarity designation

I'm not in the States. ;^) Some machines have the C dot symbol, some
don't. And BTW, some put that symbol on the nameplate, rather than
next to the socket.

I've also seen that information on the name/rating plate. Not a very
obvious place I agree.

--
Best Regards:
Baron.