Monday, December 29, 2014

Keypunch interface testing almost done, but SAC Interface connection still dead


I had one anomalous result in testing yesterday that I don't understand, so I instrumented the heck out of the interface program and will use the voluminous state output to show me where things are going wrong. I have the detailed test plan to finish up today.

I found and fixed several minor problems, as well as the one big issue which came down to a boneheaded programming move I made, reusing the same index in both an inner and an outer loop. Can't believe I didn't spot that in all the examining and refining.

The physical keypunch sticks in a clear cycle when I should reset once all cards are out of the card path. I suspect this is an oxidized contact on the cardlever relay, the one relay I didn't pull and clean up with the burnishing tool when I serviced all the others last week.

Really feeling good about condition of this interface. As soon as last step of test plan completed, this gets uploaded to a repository and shared, along with the interface design and wiring information. The python wrapper program to use this to punch decks or read decks from 1130 simulator files will be a good demonstration of flexible ways this can be used.

I decided to rewrite the parsing of the punch line to make the code a bit more straightforward, which pushes the completion of testing off until tomorrow.


I designed the logic to allow the PC to read and write blocks of core memory on the 1130, using the USB link to the SAC Interface box. Now I just need to finish fixing the problem with pins pushed out of the back of the 160 pin socket and get the USB link working again.

Well, I thought I had them all in but the interface remains inert, no sign of incoming signals and no recognition of my output signals. I did notice that the cable connector clamp had come off the cable, so perhaps some internal wires have come loose inside the connector. This is discouraging when I had gotten so far and was finally debugging and expanding the logic inside. 

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