Sunday, September 29, 2024

Finished assembly of loader and installed it on the IBM 1130

CONNECTORS INSTALLED AND BENCH CHECKED

After I soldered on the connectors, it was time to closely examine solder joints and then test continuity of every signal net. I used the schematics to beep out connections from every pin of each IC, as well as from the external connectors and the Arduino connectors. All was correct.



STARTUP CAPACITOR ADDED AND LOADER INSTALLED ON THE 1130

A capacitor between the Reset and Ground pins on the Arduino blocks the reset pulse so that the microcontroller does NOT restart when a serial connection is made from a PC/Mac/terminal, only when the 1130 powers on. 

I swapped this shield for the older prototype shield and connected it to the 1130 - three cables, two power leads and the USB cable are hooked to the sandwich. I modified my ideas for physically mounting the sandwich which will give it a lower profile when sitting atop logic gate B, on the side where the SLT cards are inserted. 

Part of the prototype testing, besides many bodge wires, was the use of a temporary NAND gate which I implemented putting a spare 0000 card in slot B7 and using wire-wrap. That logic is now onboard the shield, which allowed me to unwire and remove the SLT card. 

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