Cleaning NES games and consoles

Anyone old enough to have played with an original Nintendo NES knows the problem: You plug in the cartridge, turn on the system, and get a blank screen and the power light blinks at you. The schoolyard fix is to take out the cartridge, blow into it, then put it back into the system. Then, with a little luck, you can play your game. The trouble is, that’s just a short-term fix. In the long run, it makes the problem worse and eventually the system can’t play games at all. The solution is to clean them. Here’s a process for cleaning NES games.

Cleaning NES games for better long term results

The long-term fix is to completely and thoroughly clean the contacts on the cartridges. Disassemble the cartridge by removing the 3-5 screws in the back. Early cartridges had standard slotted screws in them; later cartridges used a weird 3.8 mm security screw. Amazon sells the appropriate bit for a few dollars.

Once you have the case open, you can see the long-term effects of blowing into the cartridge if you examine a well-loved cartridge, like most Mario or Zelda games. I’ve seen cartridges with contacts that turned green,white and black, like the worst pennies in my sons’ piggybanks. Hold the circuit board by the edges like you would a computer memory module, and clean the contacts with a pencil eraser or even a bit of metal polish on a cotton swab. Wipe the contacts down until they look like they belong in a jewelry store. Then wipe the contacts off with a cotton swab dipped in 91% isopropyl alcohol, or if you’re really paranoid, Everclear or CRC zero-residue contact cleaner. While alcohol from the corner drugstore can leave a slight bit of residue, in practice, I’ve never had it cause me any troubles.


Reassemble your newly cleaned cartridge. The board is keyed so it only fits in the enclosure one way. If you want to make future disassembly easier on yourself, you have a couple of options. If you have some early NES cartridges with slotted screws that you don’t play as frequently, you can swap those screws with the games you play most frequently. And if you have a Nintendo 64, N64 cartridges use the same security bit to hold them together, and inside, the cartridges have two completely normal Phillips-head screws that fit NES cartridges perfectly. So you can steal screws from N64 cartridges to make your Mario and Zelda games easier to re-open and clean if you want.

Cleaning the NES console itself

cleaning NES games and consoles
This is the Nintendo NES motherboard. The cartridge connector is the part in the very front. Clean it thoroughly to make cartridges reliable.

Cleaning NES games only solves half the problem. So once you have your favorite cartridges clean, turn to the system itself. All you need is a Phillips-head screwdriver, some laundry detergent, water, and an old pot. The process sounds crazy, but hobbyists have been using a similar process to remove paint off Lionel trains for 50 years. If boiling water and detergent can remove tough old paint, it can remove dirt from Nintendo parts too.

Remove the six screws that hold the system together, then remove the 15 screws that hold the motherboard in the case. Note that the two middle screws holding the cartridge connector in place are longer than all the rest; the remaining screws are completely interchangeable. Lift out the board, remove the cartridge connector, then boil the connector in water with detergent for about 10 minutes. Carefully remove the connector with a pair of tongs, then plug a cartridge you don’t mind cleaning again in and out and the connector a few dozen times. Dump the water from your pot, then bring some clean water to a boil and replace the connector. Let the connector boil for another 10 minutes, then remove the connector and let it dry.

Once the connector is thoroughly dry, reassemble the system.

Replacement 72-pin connectors

Replacement connectors are available, but I find clean originals hold up better over time than modern replacements. I have two NES consoles that I’ve kept over the years; I cleaned one in 2008 and replaced the connector in the other. The one with the replacement connector is giving me problems again, while the one I cleaned still works like it did the day after I cleaned it.

With a clean cartridge connector and newly cleaned cartridges, not renting cartridges from the video store down the street that’s been trading dirt with every Nintendo console in town, and now that you’re probably not playing it every day either, your newly cleaned NES should give you years of service. Without the blinky-blink.

Why this happens

The Nintendo cartridge connector is a poor design, but it was a marketing decision, not an engineering decision. The NES was released in the mid 1980s, when video game consoles had a poor reputation in the United States due to hastily produced games for the Atari 2600. To differentiate itself from Atari, Nintendo designed the NES to look like a VCR and deliberately left the words “video” and “computer” out of the product name.

The front-loading cartridge causes two mechanical connections between the cartridge and the motherboard, rather than the single connection in other game consoles. And the connector is looser than on other consoles. This combination of factors causes much more arcing than on other systems, and over time, this arcing causes the cartridges and the connectors to get dirty. More dirt causes more arcing, so the problem just gets worse over time.

This is why Atari consoles from earlier in the decade typically work better today than Nintendo consoles.

Nobody knows exactly why blowing into the cartridges works, but the best theory I’ve heard is that the blowing displaces dust and enhances conductivity long enough to get the cartridge loaded. The downside is the moisture also encourages corrosion, and over time, this corrosion combines with the dirt to eventually make the cartridge unusable.

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