I have a NES that hasn't been working right for years, and for a rather long time I figured it was the 72 pin connector. It would just flash on and off when a game was inserted, I used to beable to just wiggle the game and sometimes get it working, and that is THE sign it is the 72 pin right? Tonight I was bored so I decided to do some clenaing and I used 91% alchohol on paper folded over a credit card (as I usually do) to clean the pins inside. I waited just a second and put in my Marble Madness and it showed the main screen but was still auto reseting!
I think the alchohol might have not evaporated as quickly as I had thought, perhaps impoving the connection JUST enough. I want to be sure though that the pins are what need replacing and there isn't another issue to be adressed. I know there are many people WAY more experienced with NES repair than I am, so just thought I should get a consult before tinkering around.