Difference into the vias of a PCB sega cartridge

Discussion of development of software for any "obsolete" computer or video game system. See the WSdev wiki and ObscureDev wiki for more information on certain platforms.
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Manuel Baez
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Difference into the vias of a PCB sega cartridge

Post by Manuel Baez »

I have been studying the operation and the connections of the sega sonic 3 PCB cartridge and I would like to know what is the difference into the vias, beyond the form and if it has the consequences into the operation of circuit, These two types of roads can be seen in the image marked with arrows.
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InkedSonic 3 - Solda_LI.jpg
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TmEE
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Re: Difference into the vias of a PCB sega cartridge

Post by TmEE »

Only the green/blue kind are vias, rest are just drills. I am not completely sure how the boards are made but it seems to require all nets to be connected and probably for testing purposes and once done things are drilled or stamped out.
lidnariq
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Re: Difference into the vias of a PCB sega cartridge

Post by lidnariq »

The punchouts are are plating things electrochemically - that required that everything needed to be shorted at some point. The punch happened afterwards because electrically they didn't want them shorted.
Manuel Baez
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Re: Difference into the vias of a PCB sega cartridge

Post by Manuel Baez »

TmEE wrote: Tue Mar 29, 2022 8:28 am Only the green/blue kind are vias, rest are just drills. I am not completely sure how the boards are made but it seems to require all nets to be connected and probably for testing purposes and once done things are drilled or stamped out.
Thank you very much for the information, you have really helped me.
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krzysiobal
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Re: Difference into the vias of a PCB sega cartridge

Post by krzysiobal »

Most popular, metalized vias (with empty holes) are doable only on glass-fibre laminate (FR4).

This Sega cartridge uses cheaper paper laminate and for some reason, the above method does not work with it. So instead, they used some "blue" conducting substance that is filled into every hole and then somehow cemented. Drawback of this method is that legs of the elements can't be placedin this via, so elements are soldered only on one side. Just like you would do PCB in home and used wires for connecting both layers.
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