15 bit ÷ 11 bit - part the second

The next step, after constructing the base board, was to start construction of the five stacked-up boards. These are identical; the first one was built and tested, then the next four were built 'in parallel'; it's actually a lot easier making the four subsequent boards, if a little tedious.

Circuit diagrams were printed on A0 paper - the game being to highlight connections once they have been wired on the board.

Here's the completed, yet to be populated board #1:

And the testing of the populated board:

My work space - replete with Herman Miller desk.

And, after about a month of evenings and weekends, we have the five completed boards:

The pink wires supply the 11-bit divisor (M) to all boards; four of the boards have two sets of screw terminals, allowing easy daisy chaining of the divisor wires from board to board.

Amazingly, in all of this constructional complexity, there was just one error - board #2 had a single wire that went to the wrong pin of one of the ALUs. Fault finding wasn't difficult, since it's easy enough to compare expected pin logic states (from Digital simulation), to the actual chip pins. I didn't even have a logic probe; a multimeter was sufficient.