This is my version of a magnetic power adaptor for an Acer 1410 laptop, You should be able to modify the steps fairly easily for work for any laptop though. It is effective, easy to build with common materials, and takes the strain off of the internal connection and motherboard. It also holds on well enough to not come off unless it is supposed to.
Edit: There have been some changes to the design, mostly involving using thin copper foil in place of aluminum duct tape. There were heat issues involving the aluminum tape, these issues have been resolved by swapping out the aluminum tape for copper foil. Thanks to instructables members jeff-o and CyberBill for their insights and suggestions.
This modification should be completely reversible and do no harm to the laptop or original power adaptor.
Please always take your time to work safe and unplug the power cord and laptop battery.
A big thanks goes to breath for his original ThinkSafe instructable located here:
ThinkSafe: A Magnetic Power Connector for Thinkpads