One problem is that the 72 pin card is much too wide so I needed to cut and splice two sockets together. Here I marked off where to cut by opening up a NES cart for reference and used a small hacksaw.
Both sides were now finished so I set about finding the right fit and tediously testing each pin with my multimeter. Overall everything fits like a glove.
Now I needed to add some plastic spacers to connect both sides and give some mechanical rigidityso I added some scrap black ABS plastic cut to size with my Dremel and glued with some super glue.
Finally I soldered the 60 some pins with IDE ribbon cable and rechecked the connections with my multimeter. Notice how the center five pins which would be located at the black plastic are not connected on either side. This is because these were brought out to the bottom expansion port of the NES which was never used to I left these pins out.
This is where I left off for now. I still need to remove the Famicom cart slot from the Super Joy 3's PCB and solder in my FrankenCart Slot. I'm keeping my fingers crossed that everything works. If not then this was still a good exercise in modifications. I'll update this page when I make more progress.