Medion Laptop Power Socket Repair

The power socket broke due to age, being bumped around, and so forth. To inspect it, I took the computer apart, storing the screws in a little plastic bag. I measured the socket, identified all its pins, and searched for parts on Mouser, DigiKey, and Jameco. None had it.

So, I figured a possible fix would be to purchase an adapter or plug with a barrel connector, and cut it off. I went to ITC and found an adapter cord that fit, and it cost < $3. Cheap.

It turned out to have the wrong diameter for the pin in the middle. It was too small. I would not discover this until much later.

I let the project languish for a couple months, but eventually got around to it. I first tried to desolder the broken power socket. That didn't work at all, so I eventually tore it off with pliers. Tear it off carefully.

This should leave holes into which you can solder wires. I did not do this. Instead, I cut the end off the adapter cord, and stripped it, and then soldered it onto the board. This failed because the wires overheated when I put them in, and the insulation melted.

I had to remove the plug, and did... but ended up filling the through-holes. I tried to remove the solder with a braid, mostly unsucessfully. Eventually, I managed to push a paper clip through one hole (by melting the solder and pushing from below). The other pads were ground, so I decided to "surface mount" the ground wire onto those.

I stripped off more wire from the adapter cord, and pushed the "pin" or "tip" connector wire into the hole. Then I folded the strands down to hold it in place, flipped the board over, and soldered from the underside. I flow-soldered, putting the iron to the wire, heating the wire, and then melting the solder into the hot wire. The solder flowed through the wire quickly. Once filled, removed the iron and let it cool.

Then I arranged the ground wire, which was already stripped, by twisting it into a cord, and pushing the cord to fit the solder pads on the underside of the board. I flow-soldered them, making sure to get solder hot onto the pads.

I measured continuity and resistance. There is some resistance, about 100 ohms, between the + and ground, but it could still cause the continuity tester to beep quietly. To test the connections, listen for the loud beep.

The moment of truth was when I plugged it all together, and tried to power the laptop. It failed. Then I realized I needed to add the battery. That failed.

It turned out there was no continuity between the center pin and the board.

I eventually settled on shoving a small bit of solder-encrusted copper wire, flattened out a bit, jammed into the hole of the power adapter's plug. This helped the tip make contact, and the system functioned.

I then reassembled the system. But before screwing everything together, I cleaned off the dried thermal grease from the CPU, and added new thermal grease.

Reassembly took an hour, because I forgot which screws went where.

The only two issues I had were that I accidentally yanked the mousepad ribbon cable after reassembly - I wasn't going to reopen it for that because i like using a mouse instead. The other issue was the broken keyboard controller chip. It didn't work, so I just left they keyboard off. Now it's a computer with monitor and HD, that just needs keys and a mouse.

If I were going to do it again, I would have bought both ends of the plug. Then, I could replace the socket and also replace the plug on the power adapter, and be guaranteed a perfect fit.

(I just picked up a 17" LCD monitor from the street. It's missing the power adapter, and I suspect that's why it was dumped. So, to deal with this issue, it seems like I'll have to buy a set of power adapter plug and install matching plugs everywhere.)