Day 737, Replica 1 assembly

I spent Friday soldering components onto the the replica 1 plus board.

The replica 1 plus, designed by Vince Briel, is a functional replica of the original Apple 1.  Vince's design was used in the book Apple 1 Replica Creation: Back to the garage.  The book is available to download in PDF form here.

There are some optimisations in this updated design, these are mainly to reduce the number of logic IC's needed, in particular those IC's used for I/O.  I/O in this design is catered for by the use of the large IC visible on the right in the picture below, the Parallax Propeller IC.  The small IC next to the Propeller chip is a 24LC256, an industrial I2C EEPROM, often used in conjunction with a Propeller chip

Another modern addition is the USB to serial interface.  This serves the dual purpose of powering the replica 1 and providing a built in converter to enable a serial interface to another computer to be made using a USB cable.  If you've ever tried to use a serial-USB converter cable you'll understand why this is such an excellent feature - I have a skip full of converter cables with different chipsets that have all failed to work, your mileage may vary, but frankly they are crap.

The chip reduction is a nod to the techniques Steve Wozniak used to design the original Apple 1.

By the end of Friday the board looked as below but without the two IC's - prior to installing the Propellor and EEPROM chips I checked that each IC socket was receiving either 5v or 3.3v at the correct pins and that the ground pins on each were also working.  Vcc (power in) and ground are not always in the same place and some browsing of datasheets was needed to locate the correct set of pins for each different IC type.

With the first two IC's installed the replica 1 can be hooked up to a monitor/tv and tested.  The second image shows the expected output if the board is functioning, a screen full of garbage characters.  The output is in colour due to the modern Propeller chip being able to generate colour output - garbage characters include colour as well as mono.

From bare board and bag of bits to assembly and first test on day one, no soldering errors, no broken components - result.  The next step is to add the rest of the IC's and do further tests.

For official/internal use only:
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