Repairing a HP nx7300 Power Adaptor
I’ve had my HP Compaq nx7300 for over 6 years now. It owes me nothing. Over the years, I’ve practically rebuilt it entirely. It’s on it’s second motherboard, 3rd hard drive, second battery, and will more than likely need a new screen in the next few months. It’s also on it’s second power adaptor, which for the last month has been threatenting to fail. And this morning, that’s exactly what happened. Bye bye power adaptor. At least for now.
I’ve ordered a new adaptor from the good folk at laptopchargers.ie, based in Cork. But in the mean time, and with nothing to lose, I thought I’d have a go at repairing my own one.
The Right Tools for the Job
To do the job, I used only the tools that most people have in their toolbox. If you want to try this yourself you’ll need a wire-strippers, scissors, masking tape, a long nosed pliers, wire cutters, a blade, a mini hacksaw, and something to pry open the case. I used a tool for wedging up hammered nails, but a chisel or sharp flathead screwdriver will work just as well.
Opening the Plastic Casing
The hardest part of the repair job is getting the black plastic casing open. For this, I started with the blade and worked into the seam around the entire adaptor. Once the grove was large enough, I used the hacksaw to open it further until I could see that I’d broken through the plastic.
There are four little clips inside the adaptor at each corner which you’ll have to break in order for it to come apart. This is where you’ll need the screwdriver or chisel. Pry open each corner until you hear a little snap. After you’ve done each corner you should be able to lift off the top and bottom of the plastic casing.
Finding the Problem
Once the casing was off I could see more clearly where the cable enters the adaptor and how it’s wires were organised. In your case it will help to have an idea of where abouts your wire is damaged. For me, I knew it was very close to the inside of the casing as there was no visible damage to the adaptor and it could only be damaged at the point where the cable meets the board.
As it happens my hunch was right, as the majority of the secondary shielding had snapped.
Removing the Insulation
Next, I cut the power cord about one inch from the hard plastic surround at the base of the cable. I wanted to leave myself enough wire to work with at that end.
There were three parts to the power cord, an outer shielding, and inner shielding, and a central wire to carry the current. Once cut, I stripped off the outer insulation and twisted them off to keep them neat.
I then did the same thing with the end of the cable, discarding the broken section.
Here you’ll see I stripped back the cable, exposing the three different layers. I was careful to stagger the stripped insulation so as not to cause a short circuit later on. The photo above only shows two layers stripped back but remember to strip back the third blue inner wire as well.
Now that each side was stripped and all the damaged cable had been removed it was ready to be re-connected. I carefully twisted each cable together and then covered each connection with masking tape.
Next, I added another layer of masking tape over the individual cables, bringing them together and stabilising them.
In the above photo, you can see I’ve added the extra layer of masking tape. And in the background of the photo lies the hard outer protection designed to stop the cable becoming damaged by rough use. I had to slit this down the side to remove it, but having done that, it meant it was quite easy to wrap it back around the cables, giving them even more support.
Adding Back the Casing
Once the wires were fuly protected and insulated, I added back the plastic casing, wrapping masking tape at each end to hold it in place.
And that was it!
The whole process took about an hour, and costed just a few pieces of masking tape. Can’t get much better then that. The adaptor is working fine again now, for the moment anyway. I’ll update this post if I have any issues with the repaired adaptor over the next few weeks.
Here’s one more close up photo of the fixed outer casing.