Repair DC Power Jack Problem on Laptop Using Modem Port




About: DIY biologist

I fixed the laptop power jack once with non-destructive method.

Yes, I fixed it.
After three months, I heard some noise from behind the laptop.
Oh my.... again?

When I wiggled the connector, it sometimes worked.
As before, it finally stopped working.
I had to open and re-solder the power plug.

That happened .... at least 5 times.
Finally I was fed up with the re-soldering.

The problem is coming from two facts.
1) DC power jack is fixed on the mother board not to the exoskeleton of the laptop. Therefore any shock to the power connector is directly transduced to the soldering between the power jack and the mother board.
2) Joint between the power jack and mother board is highly oxidized and always ends up in un-clean solder. Even a small shock on the power jack makes the soldering connection cold.

For the solution
Fix the DC power jack on the outer case not on the mother board so that the soldering at the mother board is isolated from any external shock.

How can I do it?


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Step 1: Modem Jack Removal

There is a Perfect Hole.
It's usually unused in modern computing unless you have dial-up.
In order to reach the modem port, you have to follow this Instructable to the step 9 and remove the modem jack.

Step 2: Power Jack Preparation

As in the other Instructable, the power jack was removed from the mother board.
Then the jack is soldered to the electric cords.
The power cord is from an adapter for my old telephone. It could be any power cord.
However, it should be thick enough to support the electric current needed for laptop.
Therefore the use of those audio cable, phone cable etc. are not recommended.

Step 3: Fix It On

As you see in the figure, I glued the power jack to the space where the modem jack was originally using hot glue (I got from a $1 shop). The other end of the cords were soldered onto the mother board where the power jack was originally.

You can put the PC board back on.

Step 4: Re-assemble

You can reassemble your machine following my previous intructable.

Now you can see the empty hole which was occupied with power jack before.
And the modem port now occupied with power jack.

Step 5: Prevention

In order to reduce any stress to the newly fixed power jack, I made a restrainer that keeps any shock away from the power jack by transducing the shock to the ethernet jack.

Just cut a piece of ethernet cable and tape it back to the cable for making a small loop. Attache a rubber band to the loop in order to absorb any excessive shock. Attache the rubber band to the power cord.

Even if you pull the power cord abruptly, the rubber band absorb the most of the shock and the ethernet cable pulls the computer gently.

It certainly looks cosmetically worse than before but it works!

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    29 Discussions


    4 years ago on Introduction

    That's a nice laptop, made in Japan. You don't see stuff like that anymore.


    8 years ago on Introduction

    Something that would be even easier then this whole mock-up would be to desolder the power connector from the motherboard, clean the solder points up really nice, then put a tiny bit of hot glue under the connector then reattach it to the board with solder. Never ever comes off again. This is how we at the Best Buy Repair Center in Chino Hills, California do it. And we never seen a laptop that has come back requesting the same repair again. And we deal with at least 50 laptops a day, per technician, and we have 7 laptop technicians.

    1 reply

    Reply 4 years ago on Introduction

    That same idea immediately sprung into my mind. Glad to know that's how repair centers fix that issue. Even though I'm looking at this page three years later;Thanks 'orionsfather'.
    And a Big Thanks to 'teatimest' for your instructable, as well.


    5 years ago on Introduction

    What I do is a hot wire trace fix, similar to this Instructable but a bit neater
    Also you can use a DC Jack such as a Toshiba case mount as you have
    more surface area if you need to glue it to the bottom case, but you will need
    to use another charger or solder a toshiba male plug onto your Sony Adapter.

    I have some photos of these repairs in My Gallery @


    7 years ago on Introduction

    Great job. I was contemplating repairing my dc jack myself on my HP 6545b and have removed the motherboard. I've been kind of put off by stuff I found on the net about needing a high temp soldering iron for desoldeting modern solder (i only have a 30 watt one) so was going to get it done professionally. Got lots of quotes and one guy was honest enough to tell me that they don't do it anymore because of the high failure rate. So I think I'll go for for your method. Just a few quick questions:

    What type of soldering iron did you use?

    Do you think I'd get away with not desoldering the old jack first?

    Why do you need 3 wires? My jack has 3 sets of brass pins on the board but I'm assuming that the inner ones are positive and the outer 2 are negative. Is this a safe assumption or am I better using 3 wires.

    Would it be a good idea to put a ferrite ring around the wires?

    How durable has the hot glue been?


    3 replies

    Reply 7 years ago on Introduction

    To answer my own question the third wire is necessary as my hp power supply has a smart to allow sensing of psu wattage.


    Reply 7 years ago on Introduction

    I did not use high temperature soldering iron. Those might damage the board permanently. Just a regular 30w iron will do the job. You have nothing to lose and a functional laptop to gain. Good luck!


    Reply 7 years ago on Introduction

    Hi teatimest - thanks for the reply. I'm still waiting for the DC Jack - hopefully should be here soon. I am planning to use some 20 AWG wire from an old ATX power supply (3 pieces +ve, ground & one for the smart pin). From what I've read on the net I think 20 AWG should be fine for my PSU which is 19V 4.7amps (90 watts)? Am I correct?

    Since my DC jack seems to be firmly attached to the board (the problem is within the jack itself) I'm planning to cut it off with a mini snips and just soldering direct to what's left of it so won't need to do any desoldering after all.

    Also I don't think I'll be able to squeeze in a ferrite ring. The modem port is on the other side of the laptop so I hope I don't run into interference issues.


    8 years ago on Step 5

    I really appreciate your detailed instructions....Thank you very much


    9 years ago on Introduction

    suggestion: if you dont often use the usb port, take a usb plug, take some plastic, and make a box that the power cord goes through. then if the cord gets tugged the box takes the impact and not the power hack. and it would look a little more pretty


    10 years ago on Step 5

    I like the idea of taking shock away from the power cord but is there some other means than using up an Ethernet port?

    3 replies

    Reply 10 years ago on Step 5

    I think you might have to solve the problem fundamentally. What I did was I detached the power plug unit from mother board and attached that to the exoskeleton (see my another instructable).


    Reply 10 years ago on Step 5

    Good Idea, Another I just thought of is to use the Kensington Lock Port like this one ( and make something that can fit into the slot, so that it can hold the power cord and perhaps use magnets like on a Mac power cord. This would take shock and motion away from the DC power jack but at the same time allow to disconnect and give a little give if someone were to trip on the cord. Your thoughts, suggestions?


    10 years ago on Introduction

    Oh, I thought you were going to disconnect the modem jack connections and wire them directly to the power traces. Then hack a phone jack onto your power supply. :)

    4 replies

    Reply 10 years ago on Introduction

    I thought that, too! I was not comfortable with the idea of letting the high current running through the thin phone cable/jack.


    Reply 10 years ago on Introduction

    Please correct me if I'm wrong. There shouldn't be high current going through since the laptop usually receives power from an AC adapter with maybe 20V DC, right?


    Reply 10 years ago on Introduction

    Maybe I am just paranoid. Mine says 3.75A. (no I don't think the voltage matters, but current does).


    Reply 10 years ago on Introduction

    You are right about not worrying about voltage through a phone line: during normal operation they switch between 50V and 100V when the phone is ringing and when it is not!