I recently bought an NES (which I was told was fully functional) hoping to have some fun playing some games.
However after getting a cartridge (Mario bros & Duck hunt combo cartridge) the system flashed a blue screen and reset constantly. From what I knew this was because it was either really dirty or the 10nes chip had gone bad.
I thoroughly cleaned the system and cartridge which removed a lot of dirt however it still didn't want to function. The only plausible explanation was the 10nes chip so I followed various tutorials on disabling it by removing the 4th pin.
Unfortunately I accidentally damaged the 5th pin in the process, so in addition, is my NES even more dead than it already was now or is it still recoverable?
Side note: The 72-pin connector was cleaned too (it was not dirty at all) and all the pins were in good shape.
Best Answer
If the screen is flashing once a second, the 10NES chip is still active and you did not pull the right pin. The flashing is the 10NES resetting the console.
If the screen is no longer flashing, then you have a different problem. As a comment mentioned, pin 5 of the 10NES is not actually connected to anything.