|Maglev train in Shanghai|
NEW KEYPUNCH INTERFACE DEVELOPMENT
I did more testing and validation - still having problems getting the timing right for the read of a card going through the dup station - but the rest seems to be working perfectly. I spent time with the keypunch documentation and derived some relative timings but they don't work in practice.
|Interface being debugged|
The punch cycle is 50 ms overall, with the pins at their best point to sense at 17-18 ms into the cycle. Based on this, I assumed that the cumulative duration is 12 + 17, thus if I read the pins at 30 ms after I trigger the punching for the column, it would be the right time. However, the pins are not extended enough to make any contacts, registering every column as containing a space.
My earlier experiments found non-space results at 40ms and 60ms after I trigger a punch, not the 30ms I used which failed. I will work on this more deliberately tomorrow, identifying the range of times when the pins show good results.
SAC INTERFACE FOR ADDING PERIPHERALS TO THE 1130
I finished the corrections on the first board, installing the replacement resistors for those positions where I had mis-installed the pairs backwards. In addition, I have eleven sets of driver and receiver circuits assembled on the third board, just one more to go. One more board will be needed to hold five more driver circuits. A bit more soldering of components, then wiring of power and TTL signals to the boards, and then I can test these out.
|Boards one, two and three from top to bottom|
IBM IPAT TEST TOOL KIT
I found an interesting looking tool on eBay, a suitcase unit used by IBM labeled the IPAT 5800 unit. I saw some bus and tag terminators along with ribbon cable, which made it appear to be useful for some kind of IO channel testing. I was able to get it for a low enough price to be worth the gamble.
|Inside the briefcase|
|Control panel - selecting cable, lines and a few test types|
|Chart to interpret distances of malfunctions|