I have the same problem.
I bought yesterday a 220v adapter, it says output 12v 1000mA on the box but then in inner instructions it seems to output only 700mA: in fact the empeg often black out the screen for about a second and then come back with the battery icon on it!
Since I can't wait until monday, I have found in my old stuff an IBM adapter that output 15V (tested 15.5V) at 2.7A - since on back of empeg it says 8-16VDC I thinks it could well do the job, but I won't burn it

Rob, do you think I could try it?