So, this was motivated because I ordered a lot of 8 NES games on eBay, and only 1 of the 8 worked in my NES, and only intermittently (“tested and working” my ass).   In fact, the games were so filthy, they actually crapped up my newish 72-pin slot and a bunch of my other (cleaned) games are now acting up.  Shame on me for not cleaning the games first – my NES now has the equivalent of video game herpes.  Anyways, onto the tutorial!  DISCLAIMER: I am in no way responsible for any damage done to your games by following the procedures below.


My test subject here is a fairly well loved copy of Rad Racer, complete with awesome price tag on the back:


Front and Back


The first thing you are going to need, before we go any further, is a security bit for the 3 screws that hold the cartridge together (or 5 depending on the cartridge).  For an NES game, you want the 3.8mm security bit you can find lots of places online, and it can also be used for opening SNES and N64 carts as well.  Unfortunately, Nintendo appears to have gone with a completely proprietary fastener head, and I have never seen a security bit set that includes anything close to the correct bit.  It’s kind of a reverse-Torx, but even that doesn’t really describe it.  Anyways, once you have your security bit, undo the three screws recessed on the back side of the game cartridge, and put them somewhere safe.  They should only be finger-tight.




Once you have the three screws out, grab the cartridge down by the 72-pin connector, and gently lift up on the back half of the cartridge.  It should hinge up nicely at the top end of the cartridge.


Open Case


Separate the two halves of the cartridge case and you should be greeted with this:




Nothing like efficiently packaged electronics huh?  Anyways, the green PCB you see there is the game, or rather the board the supports the integrated circuits (ICs) that actually make up the game.  There won’t be anything holding the game into the cartridge, so you can just pull it out (hold it by the edges) and flip it over, and viola!  The chips that comprise Rad Racer (a fairly average early NES game from a hardware standpoint):


The ICs are as follows, from left to right: Infamous NES Lockout Chip, the CHR Graphics, the PRG Code, and above right is the Memory Mapper

The ICs are as follows, from left to right: The infamous NES lockout chip, the character (CHR) graphics memory, the program (PRG) code memory, and the upper right chip is the Memory Mapper


Once the PCB is out of the cartridge, you can clean the accumulated oxidation and grime off the contacts.  This game actually isn’t particularly bad or crapped up, which really goes to highlight just how finicky the NES zero insertion force connector can be.  To clean the contacts, you will want a good, static/lint free cloth and a quality contact cleaner.  A number of websites, including (not an affiliate link) sells all the things you need in one place, or you can be industrious/frugal and acquire similar items from other places on your own.  Apply some contact cleaner to your cloth, and rub it into the contacts on one side of the game.  You should get a nice black residue appearing on your cloth – keep cleaning until this stops appearing on your cloth and the contacts look nice and shiny.  Repeat with the contacts on the other side of the board.




Once the contacts look nice and clean, put some anhydrous isopropyl alcohol (or other similar chemical – make sure it is safe for cleaning electronics and doesn’t contain water) on a clean cloth, and clean off any residue from the initial contact cleaner.  Once you have removed any residue and the alcohol has flashed off, we can start to reassemble.  But first, I like to look at the cartridge case itself.  It should be fairly clean on the interior, but one place the is usually junked up in used games is the interior faces of the plastic around the 72-pin connector.  I like to take a toothbrush and some soapy water and scrub this area clean.  It’s so close to the main contacts and the ZIF socket is so finicky, it’s worth the extra 30 seconds to safeguard yourself against something sloughing off the cartridge and finding it’s way into your main socket.




You may also want to consider cleaning the ribbing on the front side of the cartridge depending on how dirty it is, just be careful around the label if it’s in good shape.  Once the cartridge case has COMPLETELY dried, you can begin to reassemble, which is mostly reversing what we’ve already done.  Re-insert the game PCB into the front half of the cartridge case, with the ICs facing the front of the cartridge (it should only seat properly one way – if you screw this up, you are beyond help).


Replacing PCB


Once the PCB is seated on the plastic extrusions, take the back half of the case and slide the hooks at the top end into the slots on the front half of the case; this forms the ‘hinge’ at the top of the cartridge.


Replace Case


Close up the case, and tighten the 3 screws back into place using the security bit.  Finger tight is appropriate here – do not over tighten or you risk breaking the cartridge case.  Once you’ve got it back together, you’re all done!  Well, I’m not.  I have 7 more to clean.


Fortunately, price tags  seem to come off NES cart plastic very easily, but a little Goo Gone will clean up any residue left behind

Fortunately, price tags seem to come off NES cart plastic very easily, but a little Goo Gone will clean up any residue left behind