How to Repair a Ninetendo Entertainment System (NES)
The original Nintendo console, the Nintendo Entertainment System (NES) remains one of the most popular gaming consoles, even thirty years after its introduction. After all these years, many of these consoles are not fully operational. However, they are fairly easy to fix. Common issues include a blinking screen, a black screen, a solid color screen, the game resetting every few seconds, and a flashing LED power light. If you are experiencing any of these, the 72-pin connector is probably bad; chances are, this is the problem.
The 72 pin connector is where the game cartridge makes contact with the system. This can become dirty, corroded, or worn out over time; this is the most common problem for the NES. This part can't really be repaired, so you will likely have to replace it. To do this, you will need just a Philips head screwdriver and a new 72-pin connector.
Replacing the connector is pretty simple. To replace the 72 pin connector, begin by turning the NES upside down and removing the six screws connecting the two halves of the unit (you don't need to remove the two screws under the controller port). Then turn the console over and remove the top half.
Now that the NES is open, remove the seven screws connecting the metal RF shield to the unit, then remove it. This exposes the cartridge tray, which is connected with four screws. Remove these, and the three screws connecting the motherboard to the console. Gently pull the motherboard out of the console, carefully, because it is still attached to the console by wires. Then remove the cartridge tray by pulling it towards you, then up slightly.
You now have access to the 72-pin connector. It may be difficult to remove, but just pull it and wiggle it slightly and it will eventually come out. Discard the old connector (unless you can think of some other use for it). You should clean the contacts at the point where the 72 pin connector connects to the motherboard. You can make a solution of water and rubbing alcohol, dip in a Q-tip, and rub the contacts with this. Use a dry cotton swab to dry it. Do this on both sides of the motherboard. Then place the new 72-pin connector in its place.
The cartridge tray is a bit difficult to put back in place. Line up the screw holes in the 72-pin connector and the cartridge tray, then pull the tray forward slightly, then press down a bit on the front part. It should click into place. Now reassemble the NES using these same steps, but in reverse.
You should also clean the contacts on the cartridges using the same strategy you used to clean the contacts on the motherboard. This is important, as the NES is prone to collecting dirt. Also, when you insert a cartridge into the new 72-pin connector, don't press down; the connection should be tight enough that this isn't necessary. Plus, pushing down on the cartridge ruins the “springiness” of the pins, which is one of the main reasons the connector goes bad.