Video does not work every time.

I recently got my old Nintendo 64 console working after years of sitting in the garage. I am able to boot up games and play them, but the problem is the games don’t boot up 100% of the time. I tend to have to power the console on and off several times and reseat the cartridge before the game finally boots up. I am thinking it could be two things, the power switch is dirty and when turned on it does not make a good enough connection or the cartridge connector is not making a proper connection. I’ve cleaned the console thoroughly yet still have issues booting up. If you have any ideas on what is going on they would be greatly appreciated. I have thought about replacing the AV cables but I don’t think that is the issue. I really think it’s a connection issue somewhere. PLEASE HELP!