Instructions
Insert your PlayStation 1 video game into your PlayStation 2 gaming system. Turn the power on and begin a new game.
Input the various cheat codes as you normally would if you were playing the game on the PS1. For example, in "Dynasty Warriors," a 1997 release for the PlayStation 1, players would unlock the character Nounga by inputting the code "Square," "Up," "Triangle," "Down," and "X." This code will work exactly the same on the PS2.
Begin a new game to ensure that your cheat codes have taken effect.