Construction of the clone started in February 2006 which is after the assignment of my final year project topic. As mentioned earlier, the biggest hurdle in completing the project is the lack of components here. For example, the ALU chips (74381 and 74382) are nowhere to be found. I ended up substituting the chips with 74181s as you can see in the picture below.|
The ALU chips were substituted until Bill Buzbee kindly mailed the actual parts. Like Bill's machine, the clone was built on five cards (the ALU, control, memory, front panel and device card) mounted inside a hand-made card cage and the cards are connected by a wire-wrapped backplane.
All the cards, clockwise from top left - ALU/register card, control card, front panel card, device card, memory card
The card cage
The wire-wrapped backplane
Also, a temporary front panel was constructed before the idea for an enclosure came along later. I started thinking about the enclosure and the new front panel after the machine started to work.
Temporary front panel
The clone with its temporary front panel. Notice the breadboard on top of the cage, this is the instruction DIP switch connected to the boot PROM socket used to test instruction. Also notice that there are no more ALU substitute board, this is because it was modified so that all the cards can fit into the cage. Look at the picture below.
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