How To Fix NES 72-Pin Connector And Lockout Chip

The first gaming system I ever owned was the Nintendo Entertainment System (NES). I was one of the lucky ones. My version came with an orange laser gun instead of the gray one.

After years and years of wear though, it began to malfunction. Luckily at the time, before Google, my good friend knew just what to do.

His great advice, “Blow On It! Everyone knows that dumbass”. So, I did and it worked… For a while, then stopped working altogether. Much later on, or after Google, I learned there was something else going on entirely.

It was very stressful for me, but worth it in the end.

— Me after I operated on my original NES and it worked

Read on and I’ll explain the whole process. Like, what’s probably going wrong and how to fix it. Along with what I used for my fix. I’m not an expert. Other issues may be causing your consoles problem. This is just what worked for me.

Try this at your own risk. I am not responsible for any injuries or issues due to following this guide. If you do not know how to Safely work with electronics, Do Not Attempt This.

That being said…

Common NES Malfunction Issues:

There are two things that typically go wrong with the NES console. And one thing with the cartridges.

  • Console: 72-Pin Failure
  • Console: Lockout Chip Failure
  • Cartridge: Dirty Connectors
  • Bonus Cartridge Issue: Dead battery for SAVE function

How To Clean NES Cartridges

Before opening up the console, make sure the game cartridges themselves are clean.

To clean the cart, you’ll need to take it apart. That usually requires a special bit tool. Those bits can be found easily on Amazon or eBay. Also, the best way to clean the cartridge connectors is a contact cleaning eraser, cotton swabs and rubbing alcohol. The contact erasure can be found on eBay or Amazon as well.

How To Replace 72 Pin Connector

The pin connector is where the game cartridge contacts the console. If the connections are bad, it won’t function properly.

Luckily you don’t need a special bit screwdriver to take apart the NES itself. (But you will for most games.) To remove the 72-pin, you’ll only need a Philips head screwdriver that will fit into the hole.

You will also need the pin connector. Some people like to refurb the pins. This is a possibility. But it can be tedious and there are no guarantees it will work.

Two 72-Pin Refurb Options:

  1. Remove 72-Pin and boil in water. After cooling and drying, the pins should be closer together.
  2. Use a scraping tool, like the ones they use at the dentists, and try to bend each of the 72 pins back into properly tightened alignment.

The details of these refurb options are beyond the scope of this article.

How To Modify The NES Lockout Chip

The Lockout chip was originally installed to keep fake and international copies of games from playing. The problem is that if the chip fails, it basically operates like all games are fakes. Another issue could be dirty carts not making a good connection. The weird signal gets interpreted as fake and disables the NES.

There are a few ways to do this. The most professional option would be to solder out the pin connector. The other is to cut and bend the faulty pin.

As long as you break the connection between the pin on the lockout chip, the console should startup every time. If you ware looking at the motherboard, it’s the chip furthest to the bottom right.

On the row of pins facing you, it’s the 4th pin from the left. That is the only pin that needs to be disconnected for it to work.

After that, you just have to go in the reverse process and put the system back together.

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