NEED A REVISION DUE TO CONTACT SOLDERING ISSUES
Having switched over to removing IBM Solid Logic Technology (SLT) card contacts from donor cards, then installing them on my PCB to allow that card to plug into the IBM 1130, I needed to change the shape of the solder pad.
When soldering the IBM contacts onto the original PCB pads I had designed, the contacts were able to twist and slip out of position because the pad shape allowed it. The liquified solder surface tension will pull components into alignment as long as the pad shape matches the bare metal of the part.
I needed to re-use IBM contacts to form my substitute for the IBM 5806223 card; that card provides the controller logic to attach the IBM 1627 Plotter or the Calcomp 565/563 which are the originals that IBM private-labeled as the 1627. These are essential to having my card snap into place in the SLT backplane, due to the unique shape of the IBM contact and the shape of the pins on the backplane.
I also added a two pin header so that someone who wishes to use my card with the 1627 model 2 or the Calcomp 563 models can insert a jumper. My logic will automatically apply the longer hold and busy times for these larger plotters when the jumper is in place. Without the jumper, the card works with appropriate timing for the smaller 1627 model 1 or Calcomp 565.
SENT FILES OFF TO PCBWAY FOR FABRICATION
PCBWay is sponsoring the manufacturing of the printed circuit cards for this project, both for the original version of the card and this revision. I adjusted the pad shape and then validated all the measurements to be certain that the card was compatible with the SLT sockets on the backplane.
Once I felt good about the correctness of the board design, I shipped it off to PCBWay.com and had them begin manufacturing. The design of the PCB will be shared on their site for anyone who wants to build this project without having to upload design files.
I am riding on the hype train :) . I know from a technical standpoint the replacement RAM board is much more interesting and challenging - none the less I am really looking forward for something new to do on our system.
ReplyDeleteThis project might not be as technically challenging but it has the tremendous advantage of being almost certain to work properly without any bizarre problems arising.
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