NES Hacks: Coin Tricks

Here in the Philippines, we had the Japanese version of the Nintendo console, known as the Family Computer (aka Famicon), instead of the dull-grey clunky unit with excessively large cartridges known as the Nintendo Entertainment System.

The Famicon design featured joysticks that were permanently connected to the console and had a port at the front which was used for the optional light gun. This port was usually covered by a red plastic cap when not in use.

There was something mysterious about that port. It has little pins in it, and wat I remember is that my uncles and cousins would take a 10 centavo coin and run it across the ports pins with Contra plugged into the game slot and the unit turned on. After a few tries they would get a level select screen.

It's a wonder how anybody figured out how to do this trick, let alone that it worked at all. The regular way to do this utilizes a variation of the Konami Code.

It would be real nice if someone could come up with a solid explanation of why it works. Unless someone already has, and I haven't found the right keywords to google it.