AC adaptor for Dell Latitude CSx latptop

[Allan Adler]

Apparently a new AC adaptor for my Dell Latitude CSx will cost me about
80 dollars. I got two different opinions from two different Dell
representatives about whether I actually need the exact adaptor
for that machine. One of them recommended something that costs about
$53 but is for a slightly different laptop. The other one said one has
to get exactly the right thing. I know someone with a Dell Latitude but
a different model and had no problems using its AC adaptor on one
occasion. So, I'm skeptical that one has to be so picky, except maybe
in connection with getting Dell to honor the warrantee. I don't know
anything about how the different AC adaptors differ in their characteristics.

Dell also recommends that one does not use the same adaptor for more than
a year and a half. I've been using my laptop for about 5 years and it was
given to me by someone who had already given it a lot of use. Dell's
recommendation applies both to the black box part of the adaptor and to
the cord that connects the black box to the wall. The latter is what increases
the price from about 60 dollars to about 80.

My guess is that the adaptor costs more than I could sell the laptop for.

What I'd like to know is whether I can find used AC adaptors for Dell
Latitude laptops that would be suitable and cheap?

The reason I want to replace the adaptor on my laptop is that I dropped
the adaptor once and there are some exposed wires. It has been like that
for a year or two or maybe longer and has not caused any problems.

I'm also interested in obtaining *very* cheap used laptops just to experiment
on them. The cheapest I've seen online is about $200, which is way more
than I want to spend. My interest in them is simply that I want to get
some experience opening them up and working on them and I don't want to
work on a machine (such as my Dell laptop) that I am using for other purposes.
I just want some experience trying to replace or swap or upgrade parts on a
machine that is of no importance to me, just to learn to do it. I have
experience assembling components in desktops and built one of my PC's that
way. I've shied away from laptops because they are reputed to be so
non-generic, but I think it is time to give them a try.

 

[Gary Cavie]

Apparently a new AC adaptor for my Dell Latitude CSx will cost me about
80 dollars. I got two different opinions from two different Dell
representatives about whether I actually need the exact adaptor
for that machine. One of them recommended something that costs about
$53 but is for a slightly different laptop. The other one said one has
to get exactly the right thing. I know someone with a Dell Latitude but
a different model and had no problems using its AC adaptor on one
occasion. So, I'm skeptical that one has to be so picky, except maybe
in connection with getting Dell to honor the warrantee. I don't know
anything about how the different AC adaptors differ in their characteristics.

Dell also recommends that one does not use the same adaptor for more than
a year and a half. I've been using my laptop for about 5 years and it was
given to me by someone who had already given it a lot of use. Dell's
recommendation applies both to the black box part of the adaptor and to
the cord that connects the black box to the wall. The latter is what increases
the price from about 60 dollars to about 80.

My guess is that the adaptor costs more than I could sell the laptop for.

What I'd like to know is whether I can find used AC adaptors for Dell
Latitude laptops that would be suitable and cheap?

The reason I want to replace the adaptor on my laptop is that I dropped
the adaptor once and there are some exposed wires. It has been like that
for a year or two or maybe longer and has not caused any problems.

I'm also interested in obtaining *very* cheap used laptops just to experiment
on them. The cheapest I've seen online is about $200, which is way more
than I want to spend. My interest in them is simply that I want to get
some experience opening them up and working on them and I don't want to
work on a machine (such as my Dell laptop) that I am using for other purposes.
I just want some experience trying to replace or swap or upgrade parts on a
machine that is of no importance to me, just to learn to do it. I have
experience assembling components in desktops and built one of my PC's that
way. I've shied away from laptops because they are reputed to be so
non-generic, but I think it is time to give them a try.

Hi Allan,

It just so happens, that in my desk drawer here, I have an adaptor which
came from a Dell Latitude CSx laptop. The part number on the case is ADP-
70EB, and has an input voltage range of 100-240v, 50-60 Hz, with output
of 20v.

If we can come to some sort of arrangement regarding the postage, you're
more than welcome to it - and I'll get it sent over to you.

Email address should be valid, but despammed.com seems to be dropping a
lot of emails at the moment, so probably best to reply on here if
interested.

Gary

 

[Allan Adler]

The adaptor is starting to fail. It fails to power the laptop unless it is
in a very specific position. I took a look at the exposesd wire with a
magnifying glass. There seems to be a thin plastic wire inside surrounded
by a kind of stranded wire that looks like aluminum. It is apparently the
stranded wire that has sustained the break. Now that I realize that, I'm
considering trying to solder it, but I've never done soldering with this
kind of situation before: first there is the stranding, instead of solid
wire, which isn't too bad, but also the fact that it surrounds the thinner
plastic (in appearance) wire. Also, it is right next to the black box, so
there is very little margin for error and not much to work with on the side
coming from the box.

If someone has advice on how to handle this, it would be welcome. I don't
know whether it is possible to open the black box. If so, I might be able
to scrounge some more length of wire or replace it.

I'm not absolutely sure that the plastic looking wire in the center is
an electrical wire. The spark when it connects sometimes looks greenish,
like the led, so maybe it is really a fibre optic cable or something.

I don't know what I'm working with. That's part of the problem.

 

[Jasen Betts]

The adaptor is starting to fail. It fails to power the laptop unless it is
in a very specific position. I took a look at the exposesd wire with a
magnifying glass. There seems to be a thin plastic wire inside surrounded
by a kind of stranded wire that looks like aluminum. It is apparently the
stranded wire that has sustained the break. Now that I realize that, I'm
considering trying to solder it, but I've never done soldering with this
kind of situation before: first there is the stranding, instead of solid
wire, which isn't too bad, but also the fact that it surrounds the thinner
plastic (in appearance) wire. Also, it is right next to the black box, so
there is very little margin for error and not much to work with on the side
coming from the box.

If someone has advice on how to handle this, it would be welcome. I don't
know whether it is possible to open the black box. If so, I might be able
to scrounge some more length of wire or replace it.

if you can, open the box, that sort oof repair in the wire done close to
the box is likely fail again soon.

Some boxs have screws hidden under labels, or under plastic plugs, or
little rubber feet.

Some boxes clip together, others are glued, still others are full of resin.
the glued boxes will often open if tapped repeatedly and lightlynear the
seam with with a hammer.

I'm not absolutely sure that the plastic looking wire in the center is
an electrical wire. The spark when it connects sometimes looks greenish,
like the led, so maybe it is really a fibre optic cable or something.

It's almost certainly electric.

I don't know what I'm working with. That's part of the problem.

when you get the box open be careful. some parts near the power inlet could
hold a high voltage.

Bye.
Jasen

 

[Allan Adler]

Thanks for the helpful advice, Jason.

 

[Allan Adler]

if you can, open the box, that sort oof repair in the wire done close to
the box is likely fail again soon. Some boxs have screws hidden under labels,
or under plastic plugs, or little rubber feet. Some boxes clip together,
others are glued, still others are full of resin. the glued boxes will often
open if tapped repeatedly and lightlynear the seam with with a hammer.

Thanks for your helpful advice. I didn't want to try to fix the adaptor as
long as it was at still working in at least one position. That ceased to
be the case recently and last night I looked up your year old advice and
started working on the AC adaptor. There are no screws hidden under labels
or rubber feet and it isn't filled with resin. Tapping the box with a hammer
didn't seem to work, although I can't say what would have happened if I had
been more patient and persistent. Instead, I hammered a screwdriver into
the seam in a few places and twisted it and eventually got the box open.
I saw a couple of little screws on the printed circuit board that were covered
with what looked like glue. When I tried to clear away a little of the glue,
the screw heads broke off. I had thought that they served to attach the entire
assembly to the bottom, which I'd had trouble removing, but that was not the
case. Breaking the screw heads had no discernible effect. Stressing the
bottom of the case a little created a little space between the plug that
receives the wall cable and the box. I inserted the screwdriver and widened
the gap (I don't remember whether I used the hammer) and soon I was able simply
to lift off the bottom of the box.

It's almost certainly electric.

It was stranded wire with white, apparently plastic insulation. There is a
rubber holder of some kind with a hole in it that is part of the wall of the
case and the cable to the computer passes through it. After I cut the
wire, I was able to slip this off. Inside the case, the wire became two wires,
one in white insulation, the other in black insulation. The former connected
to the white insulated wire forming the central cable described above. The
latter connected to the outer stranded wire that wrapped around the white
insulated inner wire. I cut away the damaged portion and exposed the wires
in preparation for soldering, which I plan to do today as soon as I create
a suitable workstation for soldering. I'll describe what happens and whether
the AC adaptor works afterward.

I am puzzled by a few things:
(1) the plug that connects the AC adaptor to the computer has 3 holes in it,
but there are apparently only two wires comprising the cable going from
the box to the laptop.
(2) The Dell representative I spoke to was quite certain I needed exactly the
right AC adaptor, and others, maybe on this newsgroup, have confirmed that
using a different AC adaptor might fry the storage battery. On the other
hand, there are only two wires going to the laptop and I don't see how
sensitive that can be.
(3) Pursuant to (2), it is natural to wonder what kinds of fancy things might
be going on in the printed curcuit board in the AC adaptor. I doubt that
I can analyze it. I don't even recognize a lot of the stuff on it, since
it looks a little to me like surface mount technology, which I know very
little about.
(4) Pursuant to (3), I'm just curious to know how hard it is to reverse
engineer such an AC adaptor starting with only one of them. I don't have
any plans to do so at the moment, but I like to know how in principle
that would be carried out. My naive guess, as I imagine doing it, is that:
(a) one constantly takes photographs of the device in various stages of
decomposition and of its components;
(b) one takes careful notes on where everything went, and in what
orientation, and in what order they were removed;
(c) one removes ALL the components and records all possible information
on their provenance and electrical characteristics;
(d) one photographs and/or photocopies the PC board on both sides (hoping
there are only two);
(e) one uses an ohmmeter to test continuity between any two possible
places that a lead to a component or terminal might go;
(f) one uses a CAD program to try to reconstruct the circuit from all
the above information and a simulator to analyze it.

How close is that to the truth?
(5) Pursuant to (4), assuming it is somewhat correct, one can then do the
same thing with AC adaptors of other Dell laptop models and see exactly
what is the difference between them.
(6) Is it conceivable that the answer to (5) does have something to do with
the third pin on the plug mentioned in (1)? I wasn't planning to open up
the laptop to look at it, since I am quite intimidated by laptops and
have never opened one up. I did build a PC from components a while back,
and it would be nice to learn how to work with laptop hardware; I just
need a reason for optimism.

 

[Allan Adler]

(4) Pursuant to (3), I'm just curious to know how hard it is to reverse
engineer such an AC adaptor starting with only one of them. [snip]
How close is that to the truth?

yeah that's about it. usually there are only two interesing layers.
an ohm meter or continuity tester can help greatly with tracing circuits.
if it's sensitive to low enough resistance it can work on circuits where
some, or all, of the parts are still on the board.
Thanks.

(5) Pursuant to (4), assuming it is somewhat correct, one can then do the
same thing with AC adaptors of other Dell laptop models and see exactly
what is the difference between them.
(6) Is it conceivable that the answer to (5) does have something to do with
the third pin on the plug mentioned in (1)?

the third pin may be for a different input voltage, or it may be used to
detect the presence of the ac adaptor. - I'd check first to see if two of
the pin contacts on the plug are connected together

When I wrote about the 3 pins, I forgot that the the cable, just before
arriving at the plug that fits into the laptop, has a kind of barrel
shape along the way, like a snake that swallowed a can of beans. Most
likely it contains some more circuitry that results in there being 3
pins. My naive guess is that it is just a simple voltage divider, possibly
with some protective stuff against mishaps that would not occur to me.
Maybe the third pin goes exclusively to recharging the battery.

 

[jasen]

When I wrote about the 3 pins, I forgot that the the cable, just before
arriving at the plug that fits into the laptop, has a kind of barrel
shape along the way, like a snake that swallowed a can of beans. Most
likely it contains some more circuitry that results in there being 3
pins. My naive guess is that it is just a simple voltage divider, possibly
with some protective stuff against mishaps that would not occur to me.
Maybe the third pin goes exclusively to recharging the battery.

nah it's probably just a lump of ferrite to stop EMI from escaping the laptop.
especially if it's fairly heavy and sticks to magnets and never gets warm
(unless in a warm place).

Bye.
Jasen

 

[Frank S.]

The "Lump" is just a ferrite block to help meet FCC EMI radiation specs

(4) Pursuant to (3), I'm just curious to know how hard it is to reverse
engineer such an AC adaptor starting with only one of them.

[snip]

How close is that to the truth?

yeah that's about it. usually there are only two interesing layers.
an ohm meter or continuity tester can help greatly with tracing circuits.
if it's sensitive to low enough resistance it can work on circuits where
some, or all, of the parts are still on the board.


Thanks.

(5) Pursuant to (4), assuming it is somewhat correct, one can then do the
same thing with AC adaptors of other Dell laptop models and see exactly
what is the difference between them.
(6) Is it conceivable that the answer to (5) does have something to do with
the third pin on the plug mentioned in (1)?

the third pin may be for a different input voltage, or it may be used to
detect the presence of the ac adaptor. - I'd check first to see if two of
the pin contacts on the plug are connected together

When I wrote about the 3 pins, I forgot that the the cable, just before
arriving at the plug that fits into the laptop, has a kind of barrel
shape along the way, like a snake that swallowed a can of beans. Most
likely it contains some more circuitry that results in there being 3
pins. My naive guess is that it is just a simple voltage divider, possibly
with some protective stuff against mishaps that would not occur to me.
Maybe the third pin goes exclusively to recharging the battery.

 

[Allan Adler]

Thanks for all the help with this problem.

I soldered the wires together. It is a very ugly job of soldering but it
works and the computer works when I use the AD adaptor now. I used electrical
tape to cover the exposed wires and more on the outside of the box to try to
keep the wires in one position, so I don't stress the soldered connections.
Hopefully that will hold.

Encouraged by this, I'm eyeing an AC adaptor that used to supply power to
my answering machine before the wire developed some internal breaks and
started providing only intermittent connections. It is a NOKIA ACP-7U
with an output of 3.7 VDC and 0.35 A. The main obstacle to getting it
open seems to be a little nut. I went to several hardware stores, including
Home Depot, trying to find a nut driver for it. It seems to be smaller than
1/8 inch. Home Depot was the only place that seemed to have a small enough
nut driver, but it was in a set selling for $16 or so and didn't seem worth
it. I could also try a pair of needle nose pliers, but I'd rather use the
right tool. I also asked at Radio Shack but they didn't have anything.

I'm not actually sure of the measurement of the nut. It is recessed in a
narrow hole, so I can't measure it directly. I was thinking of photocopying
it, but the prongs are in the way.

Since this NOKIA AC adaptor has no purpose anymore, I would consider reverse
engineering this one just for the experience.

 

[Allan Adler]

Encouraged by this, I'm eyeing an AC adaptor that used to supply power to
my answering machine before the wire developed some internal breaks and
started providing only intermittent connections. It is a NOKIA ACP-7U
with an output of 3.7 VDC and 0.35 A. The main obstacle to getting it
open seems to be a little nut. I went to several hardware stores, including
Home Depot, trying to find a nut driver for it. It seems to be smaller than
1/8 inch. Home Depot was the only place that seemed to have a small enough
nut driver, but it was in a set selling for $16 or so and didn't seem worth
it. I could also try a pair of needle nose pliers, but I'd rather use the
right tool. I also asked at Radio Shack but they didn't have anything.
I'm not actually sure of the measurement of the nut. It is recessed in a
narrow hole, so I can't measure it directly.

I've still not found a local hardware store that has such a nut driver.
I'm now fairly convinced that it is 5/32", but I don't really know.
I looked online and found some places that sell such nut drivers,
but I don't want to pay roughly $5 plus S&H for it, especially when
I'm not absolutely sure of the size. So, I've been thinking about how
to make a 5/32" nut driver. My first idea is to take a piece of steel
tubing of the right size, heat treat it to make it more malleable and
then to jam a 5/32" allen key into the hole to make the hole hexagonal,
and then heat treat it again to harden the steel. I don't have a 5/32"
allen key but but I could probably file a rod into hexagonal shape and
then taper it so that the end fits in the tube. I'm not sure whether I'll
do this. I started looking through archives of rec.crafts.metalworking to
see how people make hexagonal holes and learned about something called a
rotary broach, which is sold by http:/www.Slatertools.com for a lot more
than a comprehensive set of nut drivers costs. So, I've made no real
progress, but it is educational so far.

 

[jasen]

Allan Adler <[email protected]> writes:

I've still not found a local hardware store that has such a nut driver.
I'm now fairly convinced that it is 5/32", but I don't really know.

So, I've been thinking about how to make a 5/32" nut driver.

find a bolt that fits a 5/32 allen key and lock two nuts on the shaft.
you may need to grind down the size of the head a bit.

if it was made outside the USA could be 4mm,
but 5/32 is probably close enough.

Bye.
Jasen

 

[Allan Adler]

find a bolt that fits a 5/32 allen key and lock two nuts on the shaft.
you may need to grind down the size of the head a bit.
if it was made outside the USA could be 4mm,
but 5/32 is probably close enough.

Thanks. Yesterday, it dawned on me that I might be able to use a standard
american hexagonal socket set screw, about which I have gotten all my
information from one of French's books on drafting. I went to a hardware
store that had set-screws of various sizes but they didn't have heads and
they didn't have 5/32, but they did have metric. They said I can bring
the AC adaptor in and they'll see if they can get one of them to fit.
Using lock nuts on the outside (and presumably pliers) is a good idea.
Since these set screws are open at both ends, I was thinking of using
an allen wrench to turn it. Hardware stores around here don't seem to
be very well equipped. Ordering single little items online or from
catalogues is also too expensive. So, now I'm wondering what people
use set screws or hexagonal socket bolts for, especially sizes like 5/32",
so I can also consider scavenging them from discarded items.

I'm also considering whether one can improvise a nut driver in the following
way: take a metal rod of the right diameter to just fit into the hole in
which the nut is recessed. Maybe if the nut isn't in there too tightly
I could even use a wooden dowel. Then cut the rod into 6 congruent sectors
with cuts along the axis. Then remove a prism over an equilateral triangle
5/64" from each sector, so that when the 6 pieces are reassembled they will
form a cylinder with a hexagonal hole in it. The pieces can then be inserted
individually into the hole so that they go around the nut. When they are
all assembled, it can be turned. I guess 6 trapezoidal prisms would also
work.