An unusual Apple-1 will appear in a Christie's auction on June 15, special not just for being in working order, but for the customizations made by its initial owner.
The unit not only has a green metal casing, but 12 kilobytes of RAM -- three times the original amount, Christie's said. Also added is a 1702 EPROM (erasable programmable read-only memory) chip, which allows the computer to run programs immediately after booting instead of waiting for them to be shuttled into RAM.
The value of the machine is estimated between $300,000 and $500,000. Bidding could easily surpass that amount, given other auctions in recent years -- in 2014, another Apple-1 sold for $905,000. Back in 1976 the product sold for $666.66.
Only about 200 Apple-1s were ever built, assembled initially by Steve Jobs, Steve Wozniak, and others in Jobs's family home. Buyers were expected to supply their own casing, monitor, keyboard, and power supply, but even a pre-assembled motherboard was an advantage at the time.
Most Apple-1 units have since been destroyed, stopped working, or ended up in public collections, such as the Smithsonian Museum of Art. A quarter of the original 200 exist in any form.