I have 2 Nintendo NES systems. One I thought didn't work and needed the 72 pin piece changed, but when I turned it on the other day, it sort of worked. The people in the games came up with letters and numbers on them, the game works fine on my other system. Does the 72 pin thing need changed or what do I need to?

Secret trick: take NES cartridge, press cartridge down and waggle the cartridge inside the NES and then hold the NES down and shove the cartridge onto the pins. An alternate solution is to take a Q tip, dip it in rubbing alcohol and clean out all the dust inside your game.

"Sort of worked" is a pretty good indicator that it probably is your 72 pin connector that is grimy, pitted or too lose. The first option is to get a 72 pin connector cleaner. It's built like a NES game you put in and pull out to clean the pins. That works if the pins are not pitted or loose. You can pick one up for about 8 bucks or less. The second and (IMHO) best option is to replace your 74 pin connector. It's not that difficult, and can be accomplished with a Phillips screwdriver in about 10 -15 minutes. nesrepairshop.com supplies directions with the ones they sell and it's not hard. The pin connectors run about 10 bucks. I would go with replacing the connector or sending it in to a shop and have them do it for you if you don't want to attempt it. 72 Pin Connector for NES New