Laptop Charger

Laptop Charger

Recently, I saw a video on youtube about repairing a battery charger for my laptop. All this time, I was hesitant about opening a laptop battery charger because they were simply not meant to be opened – there were no screws for opening them up.

In the youtube video, the author managed to open up the battery charger using petrol as a solvent to loosen the glue holding the covers of the charger. I was about to siphon some petrol from my car to use for the same purpose when I thought, “Wait a minute, since he was using the petrol as a solvent, why don’t I try using paint thinner.”

Since I had some paint thinner on hand it would be much easier to try this first. If it worked, I would have saved myself some amount of hassle like walking to the car park, tinkering with a plastic tubing and trying to make it work as a siphon, transporting the petrol in a container and finally disposing of it, all the while knowing that petrol contained benzene which is a carcinogen. Well, if it did not work, I could revert back to his method.

As it turned out, it worked! The paint thinner did a great job of dissolving the glue holding the housing covers of the laptop battery charger. I managed to pry open the covers of the laptop battery charger quite easily.

In the video, the fault was traced to be coming from the output cable. In my case, I also deeply suspected that the fault was in the output cable because the charging did stop working at some instances when I was moving or twisting the wires. Since I was doing troubleshooting on what could possibly go wrong, I also checked the fuse and continuity of the incoming mains power supply cable too and found them good. I also did a visual check on the capacitors and was satisfied with their condition.

Laptop Charger output wire connection

Laptop Charger output wire connection

My suspicion was proved correct when I cut off a short section of the output cable for testing at the highly stressed joining part between the charger housing and the cable. Although there was no visible external signs of damage, the break off of continuity was inside the innermost wire core. This center core consisted of very fine copper wires insulated by about 2 mm diameter pvc. What I discovered was that some of the core wires had been broken off due to kinking, possibly during manufacture.

This output wire was special, similar to that of a signal wire. The center core wire was connected to the center pin of the connector. Immediately surrounding the center core flexible wire was a layer of copper sheathing which was also connected to the charger circuit board. These were insulated with another layer of pvc. Then came another layer of copper sheathing on top which was connected to the ground of the output terminals. The whole assembly was then insulated all around with an insulation of pvc externally.

Since the cable end protector was molded with the wire during manufacture, I had to split it in order to put the new length of cable into it after cutting off the original ends. I had to glue the cable end protector in place instead of clamping it back in the original position in the housing. With a little bit of super glue, some cotton thread to wrap around and some epoxy resin, I managed to make the joint as strong as before. Hopefully, the repair could last and I don’t have to open it up again. I would be treating the output wire more gently from now onward to avoid any kinks.

The laptop battery charger was found to be working fine since the repair.