Monday, February 26, 2007
Guide to fixing a laptop power jack. A Do-it-yourselfer
Fixing a DC power jack on your (or someone else’s) laptop can be difficult. Not knowing what you are up against is a sure sign that you won't ever get it back together. However with the proper steps, repairing a DC Jack can be accomplished with little headache.
This is by no means an official super user manual. This write up is a check list and a general guide to help you replace a DC jack without having to purchase a new motherboard or a new laptop.
Disclaimer: I claim NO RESPONSIBILITY for anyone who fails in their attempt to replace a DC jack or any damage laptops can receive following this guide. I am just trying to inform others from the steps I have taken for DC replacement and the blunders I have performed myself.
0) As step zero, it is important to make sure that you identify a bad DC jack. If a laptop isn't charging when it's plugged in combined with a very loose power jack port usually indicates you have a bad DC jack. I have also seen DC Jacks that are just fine, however when looked inside, you see it has been physically destroyed on the rear end of the jack itself. Each case is mostly different, but you will run across 3 possible scenerios.
a) The DC jack has cold solders and it just needs to be resoldered (the most common).
b) The DC jack has been broken in unseen areas of the jack itself (common diagnosis is the wiggling of the jack with the adapter).
c) There is nothing wrong with the DC Jack and it's an issue with something else onboard (uncommon, but it happens).
1) Do your research.
So you conclude that you have a bad jack. Find out what style or sort of power jack you need for the laptop. You don't need to open the laptop to find out what type of power jack you need. Go to ebay and search for model laptop + dc jack. For example, if you have a Dell Inspiron 2300, search ebay for "inspiron 2300 jack". You will be greeted with some useful results. Not only will it give you results for DC Jacks but they they look like in general. It would suck if you ordered a random DC jack that doesn't even fit inside the notebook.
At this time, it would be best to check to see if the laptop powers on. If here is enough battery juice left, turn it on to ensure that the laptop works fine. It will be essential after reassembly which I will explain later
Some models like Toshiba Satellites will have a DC jack with different pin sizes. The pin in the middle of the jack will be a different gauge or different size. It's crucial that you check to ensure that you get the correct jack size. Failure to do so will ensure you some problems when you plug in your Power adapter (ie: it won't fit). When you receive your DC jack in the mail, fit it on the power adapter that goes the notebook to make sure that you received the right DC jack.
2) Prepare and gather the tools you need. Make sure you have the right tools for the job.
- Screw Drivers (different sizes and shapes)
- Pen or Pencil
- Packaging Tape
- Soldering Iron (and soldering essentials)
- Volt meter (to check continuity)
- Basic electronics and soldering knowledge
Make sure you have different types of phillips screw drivers, flat headed screw drivers, hex screw drivers, torque screw drivers, etc. If you have never been inside your laptop, then you don't know what to expect.
3) Visual overview and time to get to know your laptop. This one is I consider an important step, but it can easily be missed.. Before I am ready to disassemble a laptop, I always look at every single screw hole, removable piece and potential issues. It's just a practice that I myself perform to help me remember where the nooks and corners are. Take about 5 minutes to sit down and rotate the laptop around and look at it in more detail.
Time to get started...
4) Remove the external devices. By external devices, I am talking about the Hard Drive, Battery, PCMCIA devices if you have any, etc. When you remove these devices, you will see screws in new places and it will obviously make it easier to access the laptop when disassembly occurs. The CD ROM from a laptop, most of the time, cannot be removed at this point. When you start removing screws, it may be easier to remove the CDROM later but not in the beginning.
5) Disassembly and documentation of your steps. This is where the paper and pencil come in. The super duper most important tactic you need to perform during the disassembly process is the documentation. I cannot emphasize enough the need to document where every single screw location and size.
The most general place to start disassembly is on the bottom of the laptop. It has the most accessible screws. Generally what you want to do is draw on a piece of paper a rough diagram of one laptop. Draw one side of the laptop per page. On the diagram, label where screws are located on the laptop. Be as descriptive as possible about the location of the screws and their location. Here is a general example of a diagram.
When you remove screws, use the tape to stick them near the hole where they came from. In case the tape fails, the diagram you draw will assist you in putting them back where they belong. Document the order in which pieces are removed. Another solution (and what I personally do) is to collect all the screws from a section, tape them in a little bundle and stick them in a notable location.
Some laptops have only 2-3 sizes of different screws. There are many laptops that have many different sized screws. Take the time and document where each screw comes from. IBM Thinkpads are nice. They actually have a sticker that shows the label of screws and screw sizes. It comes in handy. Some Toshibas also have a label next to screw holes and give you unique identifiers.
Once again, it's essential that you document each step you take during the disassembly of the laptop!
6) Handle with care. The Plate connector beneath the LCD is the most fragile piece of the laptop disassembly. That's why I gave it it's own mini-section.
It's the most fragile because if you force to plate too hard, you will snap or damage it. Some models have it just tied down by a few screws underneath the laptop. Most models have a snap action to it. It comes in handy to use a very super duper thin flat head screw driver to probe the plate. If the screw driver bends too much, then it's time to probe in a different section. Please be cautious when doing this. A good place to probe is on the hinges where the plate overlaps next to the LCD hinge. When you start pulling up on the hinge from the corners, it will start exposing the parts underneath it.
(Note: The LCD display will not have to be disassembled fully. Just the cord and hinges can be removed alone. You do not have to get into the insides of the LCD.)
7) Motherboard access review. You've disassembled the laptop and you have the motherboard in your hands. Look at the DC jack and it's connection to the motherboard. The most common issue I see with DC jack failure is cold soldering or failure in the solder itself. Most of the time, the jack can be repaired by re-soldering the current DC jack in place. Some of the time, the DC Jack itself is damaged and needs to be replaced.
8 ) Replace / Repair the DC Jack. If the DC Jack needs to be replaced, use your soldering iron to heat up the solder from the DC jack and remove the old jack. If you have a DC jack with hooks or curves in the connector, good luck. I know how much it sucks removing this type of DC Jack, but with some patience and persistence, it can be done. When the DC Jack is removed, go ahead and solder in the new DC Jack into it's slot.
Warning: Some motherboards have very thin rings around the DC Jack connectors themselves. The older sony Vaio laptops have them. If you heat the solder too hot or too long, these rings come off. When that happens, you might as well call it game over. These rings connect the DC Jack to the motherboard using extremely thin connections. The rings are vital to the DC Jack connection to the motherboard.
When you get the new DC Jack in the slot, you have the option of putting hot glue around the corners of the new DC Jack. It's an option to prevent the DC jack from getting bumped and pushed too much from the AC Adapter. It's just added strength. Just don't over-do it if you decide to put some on.
BE CAREFUL ABOUT THE CHIPS AND ELECTRONICS AROUND THE DC JACK!
I have destroyed chips on laptops because I was not careful when I was de-soldering and soldering. A sharper soldering iron is a better tool than a blunt rounded soldering iron. Trust me on that.
9) Test your continuity. It sounds impossible, but you can test to make sure that you connected your DC Jack correctly. Most volt meters have a continuity checker on them. Check to make sure the grounded section of the DC jack properly grounds, and if possible, check to ensure that the positive pin on the DC Jack is properly connected to the motherboard. You can do this by touching some of the diodes on the motherboard close to the jack. You will know if it registers.
10) Reassembly with a little faith. This is the moment of truth. If you documented your disassembly well, then it will be your roadmap to reassembling the laptop. Start reassembling the laptop in the reverse order in which you disassembled it. Make sure you plug in every little cord, and ribbon back into your laptop. Disassembling the laptop again because you forgot a wire or ribbon is just annoying to the max.
11) Testing the laptop. Test the battery first to make sure that the laptop turns on without the DC Jack. There have been a few laptops that I have worked on that didn't turn on after I reassembled it. It sucks, but it does happen. Sometimes you damage something during the whole process, but with caution it can be avoided.
Once you verified the laptop turns on with battery, then go ahead and plug in the DC Jack. First sign it works is the "Battery charging" light turns on and you know you have a successful replacement. At this point you can turn on the laptop and your job is complete. If your laptop doesn't turn on .. well.. go back to step 4 and 5 and go from there. It can happen, but I haven't seen it too often unless there are more problems with the laptop than originally thought.
I hope this gives you a general idea on how to replace a DC jack on a laptop. It's not a perfect guide and I will edit it as necessary to clear the rough edges up.