By far, the most common piece of hardware to fail on any laptop is the DC Jack (the plug that accepts power on the laptop). There are several reasons for the high failure rate but the two most common are poor handling and poor design. I would say over 90% of these DC jacks are soldered right on to the motherboard.
Every day abuse of plugging and unplugging the AC power source wears down the solder connections on the motherboard. Here are the two common symptoms for this damage:
– Laptop will not accept external AC Power. Constantly remains on battery, till the battery dies.
– You have keep moving the cord around till it starts accepting external power.
First thing you need to do is eliminate the cord / power supply as being the source of problems. The power supply is the box right on the AC cord. Some power supplies have an indicator light to show when they are plugged in. If the light is working then it is not the power supply. If your power supply does not have the indicator light get a voltmeter, plug the laptop cord into the wall and using a voltmeter check the end that goes to the laptop. Insert one lead inside the opening and place the second lead on the outside. Make sure your meter is set to read DC Volts. Now if you get a reading, depending on the laptop there will be somewhere between 14 to 19 volts then your power supply is good and the damage is to the DC jack on the laptop motherboard.
Repairing the DC jack on any laptop is a major repair. If you do not feel comfortable doing it please contact a person who is qualified for the job. This repair will require dismounting the whole notebook, and removing the motherboard. Please read the following article on what steps should be taken to ensure proper care when disassembling a notebook: Notebook Repair .
Once you have complete access to the DC Jack you will see the pins that get soldered to the motherboard. To the naked eye it might look like nothing is wrong with them, but a slight break in the solder will cause these problems. You will need a soldering iron with a very fine tip. The fine tip is to avoid damage to adjacent components. Apply the solder to each pin making sure the solder gets evenly spread. The solder should have a dull look to it when you are done.
Once you have soldered all the pins, reassemble the notebook and test it out. To avoid this damage in the future take extra care when inserting and removing the external power cable. Hope this helps!