90W AC adapter getting *very* hot. (Inspiron 1420).

A few months ago I bought an Inspiron 1420, at the time they were giving the 90W power supplies away with them. I've been noticing that lately the adapter has been getting hotter and hotter whilst charging the battery. Last night it got so hot I could not even touch it and had to carry it around by the cord. It had a slight smell of burning plastic/hot electronics.

 

The adapter was still working fine, it was charging the battery, but it was just very very hot. I have 2 batteries, both the 9-cell types. Both last very well, but both cause the AC adapter to get very hot.

 

Model number of the power adapter is:

90W AC Adapter LA90PS0-00

 

Serial number is:

CN-0DF266-71615-775-8FF2  Rev. A03

 

Anyone have any thoughts? This is a very real fire concern. The adapter was on a hard floor with nothing in its immediate area to cover it.