Charge your Lenovo laptop with a benchtop power supply

It happed to my that I forgot my usual charger at my parents home about 2 hours away. The only problem I had was I really needed my Laptop to be able to work. So I looked into my rectangular charging port and saw a pin in the middle and on the sides some connections as well. I thought "well that's easy lets just check the polarity on the web".... FAIL! This connector really is strange... The center connection is a indicator-pin which has to be linked in series to a 290Ohm resistor to ground. The outer shell of the connector is the ground connection, which was relatively easy to connect to via some pirate hook cables. But now comes the difficult part... the connector has a connection on its inside apart from the huge pin in the middle... That's the positive connection. After nearly half an hour I managed to get a connection via some pirate hooks. A quick measurement was taken to ensure there was no short circuit. And finally I attached the power supply. A lot of work for something that simple...But at least it has worked for me!