Thursday, October 30, 2014

Very light day working on the system

Between heavy work obligations and an afternoon at the dentist, I only had two hours to spend in the workshop today. Still, I did make a bit of progress.


I removed the added wiring inside the keypunch and began to wire it with the new preferred push on connectors, on the assumption that the old connectors were bridging to the wrong wires because they weren't very secure. While I was at it, I used larger diameter wire which I will install on a DB25 connector.

With all the wiring disconnected, the keypunch was still misbehaving. It worked fine with a card registered in the punch station but once there was a card registered in the read station as well, the card lever relay won't activate so punching or spacing is not possible. At least I now know this isn't a flaw in my interface design.

As soon as this is debugged and repaired, I can resume testing of the interface. While I am working on the keypunch wiring, I am also replacing the read cable connections as the pins I used are also insecure, very wide and exposed at the top where they can touch other pins.


I soldered a few more driver and receiver circuits onto the board, until it was too dark to see on the outdoor work table I use for assembly.

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