This is more of a demonstration of creating this game and then showing how it plays. There are also 2 videos that show me creating similar cartridges :D Please watch them if you are interested in creating reproduction carts.
Embedding is possible but a but wonky. Try putting your cursor at the end of the YouTube link and press enter. Then hit the publish button again. It should work.
I watched the first video and saw the fast motion soldering. Is there a clip where you explain the circuit? I know nothing about the special cartridge PCBs.
Still didn't embed :( The earthbound one shows the basic wiring for this type of project. When I get done and finals are over I will have more time and can possibly do a better explanation video :)
Mostly it is a chip swap, I posted a link to a video if you want to see exactly what is done. You do have some rewiring to do to get everything working as the original NES mask rom pinnouts are not the same as your standard eprom. I really wish there was a way to embed video directly into this page as that is how I prefer to document my projects. That way NOTHING is left out :D
Oh, also check out the other two video links as well, one on Mr Gimmick basically shows you the basic technique for removing large ICs and the other is a short video on the wiring used to match the NES mask rom using a common eprom.