This is my original 7800 that my parents got for me for my birthday back in Oct 1987 as I recall. While the SN on this would indicate otherwise, it actually contains an original '84 made mainboard with the expansion port installed. It is also fully compatible with all games in the 2600 library. The mainboard shows rework from the factory with added jumper wires and resistors on the bottom of it. So I assume this is a refurbished 7800 that Atari sold as new. It does not have the hole in the side of the case for the expansion port. This one I modded with the Eckard's DEV OS 1.0 in it for development and the ability to dump and send to carts. No other modifications. I keep it in the box with all the accessories.