This Apple 1 circuit board was restored to working condition in 2013 by Ralph Simpson and three Apple engineers: Dr. Wendell Sander, Allen Baum, and Dan Kottke. On June 18, 2013, Steve Wozniak powered it up at the History San José Collection Center, making it one of 19 working Apple 1s out of the 62 known to exist at that time, largely in the hands of private owners. Only 200 Apple 1s were manufactured, of which 175 were sold between May 1976 to Oct. 1977. The first batch of 100 were made without a PCB manufacturer identified, like this example. The second batch of 100 were made by NTI, with its logo printed under "Palo Alto." The original Apple 1 included only the motherboard and chips -- the buyer had to supply the mounting board, transformers, keyboard, monitor, additional memory, cassette interface card and cassette tape player. The two larger white ceramic chips on the bottom left are the 6820 PIA chip (Peripheral Interface Adapter) and the MOS 6502 microprocessor chip. The white ceramic 6820 is very rare, the only known examples are the press photo (that machine is missing) and the first hand-made Apple 1 bought by Wozniak and given to Liza Loop. During the press event at History San José on 18th June 2013, Wozniak stated that the History San José Apple 1 appeared to him to be an early hand-built version. The date code on the 6502 microprocessor is 1576, meaning it was made in the 15th week of 1976. This would place it in the first week of April, 1976, coincidentally the date of incorporation of Apple Computers.