Re: Inspiron 1525 Problems
I believe the problem is caused by the laptop socket failing to make contact with the centre pin of the power supply plug.
The power (high current) is carried on the coaxial barrel of the power plug, inside and out. In the centre is a small pin that connects to a chip in the power brick to identify the power supply type/model. If this doesn't connect you get the "unknown power supply" error and the laptop will run on the power but not charge the battery. The power LED will also stay off.
My workaround was to pack out the centre of the laptop's power socket with some fine copper wire strands, these then made the contact between the pin on the plug and the centre of the socket and everything went back to normal.
Apparently the springs in the centre of the socket lose their grip fairly easily and this is a common problem / design fault.