There are 3 main reasons why they become ineffective. The first is the original connectors placed by nintendo in the NES would corrode and nearly rust making it impossible for the connection (if you look at one, sometimes the pins will be green like a copper penny). The connectors from MCM are made from a different metal alloy that nearly prevents this from happening. Second is "gunk" buildup from your cartridges transfer to the connector, therefore no connection again. The last reason is the connectors pins will eventually become "loose" (the game slides in the NES way too easy. This happens to heavily used NES's) therefore, no solid connection........not working. That is what I have come up with in my years of fixing NES's for friends and family. Make sure you clean ALL of your games thoroughly after you replace the pin connector, then you should be all set.


I would HIGHLY recommend replacement over repair of them. Trying to repair them is pretty much a waste of time, but it could be worth a try if they are just filled with gunk. Those are my thoughts. Hope it helps.

Danny