The Atom was Acorn's first 'serious' kit machine after the System 1 and sold in pretty massive numbers in 1981, which doesn't really explain their apparent rarity. 6502 based, and populated with as much as 8K of memory, normally made up with my favourite Static RAM chip, the 2114. Sadly the 2114 doesn't survive very well, so a couple of my 8-bitters are not well purely because of these chips.
Several add-on kits were available for the Atom, including a hi-res colour board. More info to come, but can you guess what happened to the Atom's successor, the Proton? (hint: "Auntie Beeb")

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