For those wishing to build their own AC/DC power adapter, I have successfully adapted a Digikey 9V/4A transformer.
Previous exercises with the charge port taught me that it'll disconnect current as soon as the input voltage dips below 9V. It took me 2 AC/DC adapters to get this right. The first one was “rated” 9.5V/2A and the second was 9.5V 2.5A. Both were purchased from eBay sellers as DVD player adapters and are clearly marked as identified above, but are unable to “hang” when it comes to supplying my eepc power to charge. They both work if I remove the battery, but that wasn't my goal.. I wanted a cheap solution for charging.
Here are the part numbers from Digikey that you need to order if you wish to do this right:
AC/DC Power Transformer
4.7mm Power Plug
You will need to cut off the existing 5mm plug and replace it with the 4.75mm one referenced above. Also be careful when wiring it up… unlike most cables (at least mine) the wire with printing on it is the negative lead and the print free one is positive. Be sure to use a Voltage meter prior to soldering connections to verify you've got the polarity right.
Many universal power adapters come with a set of plugs (the plug size is dependent on the voltage). If you have one of them in the drawer, you can improvise with one of those plugs, although you will probably need heat-shrink tubing to make it look nice.