Many thanks to Stuart Northfield for finding this in his loft and deciding it needed a good home :) The Mac 512K was released in late 1984 and allowed the user to work with much larger files and applications since it had 4 times more memory than the original 128K machine. For this reason it's called the 'Fat Mac' :) Other than that it doesn't differ from the original apart from the obvious difference that the name badge on the back panel says 'Macintosh 512' instead of 'Macintosh'; like it and many other compact Macs it has the development team's names embossed in the back cover so don't let any shyster on ebay tell you otherwise - I think all compacts up to the Classic had the names inside.
This one is still running nicely though the floppy drive needs to be regreased - a common fault with this era Mac. In the pix it can be seen happily running the 128K's System 1 software.....ah the heady days when you could boot an entire graphical OS from a single 400K floppy and run it successfully in as little as 128K of RAM! What happened?! Oh yes, bloatware :)