Wednesday, November 5, 2014

Keypunch interface in final paces of checkout before release of beta code, with just a few minor issues with the card reading function

Today I didn't have a lot of free time and what I did have was spent at the Computer History Museum helping out with some tape drive, card reader and power up issues on the 1401s. I also worked on a new faster way to scan in manuals which I can use to ensure all documents I have are preserved digitally on bitsavers.

NEW KEYPUNCH INTERFACE DEVELOPMENT

I opened up the punch cable connector and replaced the treacherous pin 20 which supplies the power for the release function activation, since it keeps popping out rather than sliding over the mating male pin of the socket on my interface box. With that corrected, release worked perfectly as expected.

I next fiddled with various delays until I found I could sense the pin values consistently during reading at 60ms after the trigger of the space - I am dropping the space solenoid at 20ms after trigger, then wait another 40ms before reading the sense pin values.

I found some small flaws in how I am recording the values and displaying the resulting card image, which I will fix in the code and do some final testing tomorrow. Once I have read working satisfactorily, everything is ready and I can release this to the other project members for their testing.

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