Thursday, May 26, 2016

Adjusted punch of 1442, lacing disappeared, now working on cornering station ejection


Did some initial diagnostic work to zoom in on the problem of my 1442 punch allowing the punches for rows 4 to 8 to be activated on every rotation of the motor - thus randomly lacing cards passing through the punch station during an NPRO.

I tried with my SAC Interface box powered down - same results. This means it is not my logic injecting bits into the machine. I checked the secureness of the main signals cable where it attaches to the 1131 - looked fine. I did try to feel for a magnetic field during operation, using a screwdriver near the punch solenoids, but no luck with that.

I looked over the logic diagrams for the SLT cards inside the 1442, to see if there was a common card for just those five rows. That did not pan out. Next, I looked at my ALDs for the adapter logic inside the 1131, to see if there is a common card that might explain this symptom. Nothing fit the symptoms there either.

I moved on to the mechanical adjustments and checks. I soon came to realize that the magnet assembly mounting screws were loose and the assembly was skewed away from the bottom row punches. I tweaked this and tightened it down so that no punches were activated on NPRO cycles. I may have to play a bit with it to ensure that all desired holes do get punched, but for now it is good.

Next up, I have to face the puzzling symptoms - I only saw rows 4 to 8 punch but from the top I can see that the interposer is active for row 9 as well, but the cards didn't have that column punched. Right now, I have a small wedge of card that tore off in the punch station area which I have to clear before I can go back to my tests and adjustments, but I am moving forward nicely.

It appears that the wedge is not a piece of card, but a stuck punch - perhaps the row 0 - with the interposers and remaining mechanisms unactivated it is stuck down. I will have to figure out how to deal with this, hopefully without having to remove the punch unit and disassemble it.


I received my EMM 32K x 18bit core memory module today and immediately ordered the +15V, -15V and +5V power supplies needed to use it. I will set up a quickie FPGA design to drive and test the core memory in various ways - timing, bit retention, holding various patterns. In the interim I can plan out the way I would interface to this core from the 1130, design circuits, layout the implementation and the rest of what I need to make this work. 

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