Posts Tagged ‘ac’

Dell Laptop A/C Power Cable Images

Saturday, February 12th, 2011

After a month of off-and-on power issues with my Dell Inspiron 1525 Laptop, the A/C power adapter finally stopped powering the laptop. It had stopped being identified as an authentic Dell charger a couple months ago, as I wrote about here.

I was quite certain that the power cable had broken internally due to the constant flexing.  It’s happened on almost every laptop that I’ve owned.  Slightly jiggling the power cable approximately where it flexes during natural use would cut power to the laptop.  Putting little stresses in the cable with twist ties would sometimes make the power work for a few days.  These fixes were really temporary – they only  put off the inevitable complete failure.

The options are to buy a band new authentic Dell PA-12 (or higher rated) power adapter for more than $100 directly from Dell, buy a 3rd party “compatible” charger for about $20 from eBay or DealExtreme.com (but I don’t trust 3rd party items when they plug into the household power… I don’t like fires), find a used authentic charger, or cut the cord and solder things up again.

So, the other day I cut the cable.  Here are a couple pictures that might make it easier for anyone who needs to do this in the future.

 

 

Dell Laptop Cable Inside - Cable Half

Dell Laptop Cable Inside - Cable Half

 

 

This is the cable half of the cut. You can see the top of the magnetic field minimizers… the name of which escapes me right now. There are three conductors. The tiny one in the center is for the chip in the PSU that tells the laptop whether or not the charger is an authentic Dell device – in my case, this broke months ago, when the Dell battery stopped charging – even after re-soldering, this charger still does not register as authentic; there must be another break further up the cable. Then two more layers of conductors.  I’ve covered off the outermost in red tape as I prepare to re-solder things together.

 

 

Dell Power Cable - Plug Half

Dell Power Cable - Plug Half

 

 

This is the plug half of the cut.  I’ve removed some sort of epoxy or hot-glue that held the above wires together in the form that fit inside the plastic shroud.  I think it’s hot-glue because it seems to hold the shroud over the plug.  I managed to pull the shroud off without cutting it, by running a unrolled paper clip around the edge, breaking the glue’s bond a little at a time.

As I expected, the outermost strands had all broken from repeated movement. You can see the random fraying in the strands at the top left.  Also, the center wire was clearly detached.  The 2nd conductor, white, on the right, was OK.

I’m not very good at soldering to plugs.  I tend to melt the plastic badly before getting the metal parts hot enough to solder.  So, instead of disconnecting the stubs left over in the image above and soldering directly to the plug,  I decided to trim them up and splice the wires together and inch or so from the plug. The middle wire I soldered directly.

Then I used hot glue to keep things from flexing, then wrapped it all with  electrical tape.  The end result is passable, but not pretty, so I won’t post a picture. And my Dell lives for another day… I’m using it to type this post now!

Comments appreciated!

 

 

Dell Laptop, plugged in, not charging in Vista

Monday, July 19th, 2010

My Inspiron 1525 has intermittently not been charging while plugged in. It’s gotten worse, as many intermittent problems tend to do. So, it was time for a bit of research.

It’s intermittent, so the charger generally works. I do have some battery life when it’s charged, so the charging circuits and the battery do work, though, this two year old battery doesn’t hold much power anymore.

If you search the web, it turns out to be a relatively common problem – remember, Dell sold millions of these laptops, you would expect a few problems to be reported. This laptop power connector consists of a pin in the centre of a circular connector which itself has two metal contacts, one on the inside and one on the outside of the circular ring. The inside pin is used to identify the A/C adaptor as being an authentic Dell charger. If the centre pin does not make contact with the socket on the laptop, then it will not charge; however, it will still work while plugged in.

A couple references:

– http://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed
– http://www.tomshardware.com/forum/9519-2-dell-laptop-power-jack-pinout

So, I ever so slightly bent the inside pin to the side so that it would make contact again, and it seems to be working. I’ll wonder how long it will last though.

Given how often I move my laptop around, I think it was just general wear and tear rather than a manufacturing problem. Though, I wonder if there was a legitimate purpose to the identification pin. Can an non-authentic Dell power brick really damage the battery charging circuits, while still being OK to power the laptop in “plugged in” mode?

[Edit: Hmm… upon reading some more about this, new laptops might need a way to communicate with the power brick to determine maximum power output.  If the maximum output of the transformer is too low, then the laptop can skip the battery charging to keep total power consumption down.  This also would be useful in “airplane” mode where there is a very limited amount of power from the outlet.]

Anyway, I’ve had a very similar problem happen with a cellphone charger a couple years back, so the fix wasn’t all that unique. Let’s hope that someday we can all have magnetic power connectors like the Apple guys…