The first missing IBM 1410 ALD Sheet

Ran into the first case of needing to reconstruct an Automated Logic Diagram (ALD) page, as part of my ongoion IBM 1410 FPGA implementation project.

The page for the 2nd and 3rd Scan Controls, 12.30.04.1, was missing from my diagram set. I did have information about how many gates from which cards were present on the diagram, gleaned from the card location charts. Fortunately, the Instructional Logic Diagrams (ILD) covered the missing page. Between the two I was able to construct the page, using the original gates, and other than logic block placement on the printed sheet, I expect it is pretty accurate.

I only hope all of the missing pages are so “easy”. Easy is in quotes because on the 3rd Scan Control latch, there is a collector pullover to logic 1 to reset the latch that is not common. That same situation exists with the same card type (DFA), so I was able to verify the gate utilitzatin.

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