Alright, so a few years back I refurbished myself a NES. When I buy my games I clean them before even testing them out to eliminate chances of cross contamination.
Recently I got a set of Castlevania games for it. Now, I always leave my NES on (often times will pause the game and leave it on) since there's no save points...
anyway, after only an hour or two of the console being on the game's graphics scrambled and it locked up. I took the cart out to check if the pins were clean and man, it was HOT.
Anyway, the next day I'm playing again and on the same level it locks up and the cart was hot.
I've never played a game for hours on my NES and then swapped carts without there being some sort of break between them (either i'm playing in short bursts and changing games or I'm playing for a long time an then turning it off after burning out heh)
Do NES carts get hot? My NES has never locked up on me either. The console wasn't bumped or anything so nothing could have disrupted the connection.