Monday, August 24, 2015

Testing Paper Tape Reader for 1130, plus other news.

SAC INTERFACE FOR ADDING PERIPHERALS TO THE 1130

I did locate one of my Arduino Mega boards and began hooking everything up. I had to find the 48V power supply I cannibalized from some Cisco gear and wire it up with a switching transistor that could handle the inductive load of the solenoid with its back-EMF when shut off. Slowly and steadily I identified signals from the tape reader mechanism, set up the clutch pick logic and wired it up to my SAC Interface box.

When I fired it up, I could see the clock and data lines active outbound from my fpga, but I am not sure that the Arduino is receiving the frames. One issue appears to be a startup point for the link, some set of bytes that will be exchanged and both side starting normal operation once they see the agreed pattern from the other side.

I also need to instrument up both sides, so that I know what is happening internally. I have some LEDs and scope points I can use on the master side (SAC Interface Box) and can hook up other LEDs to display the state of the Arduino slave.

While the link seems to be working incorrectly, sporadically the conditions were right to trigger a burst of paper tape read commands. If I can get the link working properly first, the rest should shake out easily.

REPAIRING DOCUMATION READER INTERFACE

I had blown out the USB to parallel port board used with the Documation reader to convert physical card decks into PC based files that could be used with the IBM 1130 simulator as well as my interface unit to the real 1130.

The replacement board was three days late, thanks to poor USPS performance, but it arrived this afternoon. It is almost dark out, so I will do the connection and testing of the card reader tomorrow morning. I need to power up the data center shed, where the reader sits, and could use daylight inside.

PARTS FROM AN 1130 ARRIVE, A GIFT FROM A FRIEND ON THE EAST COAST

A friend is thinning out his collection and thoughtfully sent me two parts from an 1130, the rotary mode switch plate and the start/stop switch for the internal disk drive. My replica of that switch plate uses a switch that doesn't detente at the same angles as the 1130 used, so that my labeled positions and the pointer of the knob are out of sync. This plate will definitely improve the fidelity of my replica machine.

1130 parts I received from a friend

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