As Mario 3 was running, I figured I'd get the two flutes in world 1 and a couple of 1 ups, then warp to world 8 and leave it there. When I returned later that evening to take another piss, I saw the game over screen. Someone has actually been playing that evening. Funny. And someone during the party actually asked me how I did the warp trick. I wanted to show him, but it got a little crowded in that tiny bathroom and someone bumped into the NES. That caused the NES to fail and after a couple of attempts we couldn't get that game to work anymore.
This was obviously contact failure. The owner said that he already tried to replace the 72-pin connector, but that didn't help much. I enjoyed myself a lot during the party he hosted, so I offered him a free repair. And let's have a look at the replacement connector.
Contact failure is really kicking in nowadays on these vintage cartridge consoles and there's a lot of bad advice online on how to fix this. Take the Angry Video Game Nerd for example, who has a lot followers on Youtube. He made a video about this phenomenon, featuring his glitch gremlin. His repair advice starts at 03:28.
A generic cleaning solution is not what you should use to clean electrical contacts. Depending on what you use, this might appear to work, but probably only temporarily. I am pretty sure that he is doing this procedure a lot, whereas a good repair should make it disappear for a very long time. I am also pretty sure that some of the glitches I am seeing in this video are caused by crosstalk in the PCB signals, and that's probably due to moisture. He probably tried that cue tip repair just before recording it. Usually, games just won't load at all. This NES gives a purple screen and a blinking power led.
My weapons of choice in this repair are three cans of contact spray from manufacturer Kontakt Chemie: Kontakt 60, WL, and 61. I learned about these products during my youth with audio gear. A lot of vintage audio gear also suffers from contact failure, in the switches, potentiometers or faders for example. In that community, it's common knowledge that these products will fix bad contacts, and I am now sharing that knowledge with the retro gaming community, because this stuff really does work great.
Kontakt 60 is the contact spray, WL is a washing liquid and 61 is coating and lubricant. The manufacturer recommends these sprays to be used in that specific order. It's easily available in Europe through Conrad, but this might be hard to obtain anywhere else. I know that the owner CRC Industries sells their own contact spray and lubricant in the states, and that will probably work equally well. A lot better than generic cleaning solutions.
I have done this repair numerous times, for instance on an N64, a dj controller and even my bicycle led headlight that all suffered from contact failure, but I never repaired an NES before. With an N64 or SNES, you have easy access to the game connector, so you can perform this repair without opening up the system, which is nice. On the NES however, the cartridge connector is situated pretty deep, and the push down tray is also very squeaky and could use some lubrication. So it's needed to completely disassemble it. Fortunately, that's really easy. I knew that the cartridge connector had been replaced, so I kept in mind that I might have to fix some bad soldering. I was very surprised to learn that the cartridge connector had an edge mount connection to the motherboard as well, rather than soldering.
I had to use serious force to unmate this connector from the motherboard. I could hear the contacts scratching and there's evidence visible that confirms contact scratching. You can feel the scratching with game cartridges too.
To fully repair connection issues, it is vital that you clean the entire signal path. In this case, that means the motherboard edge, both connectors on the replacement part and the cart edges in all game cartridges. Apply a generous amount of Kontakt 60 on the contact area and wash it off with Kontakt WL. I don't see any reason to use cue tips, there is nothing that could be damaged from contact spray in the games or the console. You should be careful with that stuff around motors, sensors and opto electronics like a dvd drive or a display, but the NES doesn't have any of that. After applying, you just let it dry or use an air compressor.
Kontakt 61 is coating and lubrication. With lubrication, you need to be aware that this makes the connector vulnerable to microscopic particles of dust. This means that contact lubricant should preferably not be used on exposed connectors, such as your game cartridges, a Game Boy or the Atari 2600. The dust cover on an SNES or N64 will work just fine and those are obviously a little better by design compared to an NES, but it will have to do. Because I know this replacement part is seriously scratching, it really needs lubrication. It's okay to do your motherboard edge too for the coating. But don't lubricate your games. Make sure your system is completely dry after all the contact spray. Spray as little as you possibly can, but make sure you cover the entire contact area. A good technique would be to obviously use the straw on the can, give 1 short spray at a time and slowly move from left to right for the entire length of the connector.
After lubrication, the contact scratching on the motherboard is gone and the force I have to apply to mate or unmate this connector is significantly reduced.
The squeaky sound when pushing down a game is caused by the springs on the sides. This is mechanical, so I would recommend lubricating these with the best mechanical lube there is: WD-40. The NES' dust cover was squeaky as well, also fixable with a little WD-40. The center slider on the front wasn't making any bad sounds, but I gave that a little spray as well.
After reassembly, the game would run, but it had terrible RF distortion. The cartridges are digital, so a bad connection over there would never cause RF interference. I immediately turned my attention to the RF cable assembly, and it took me a while before I figured out there's nothing wrong with it.
The culprit is this RF channel switch on the back. Wiggling it around a bit would fix it, but you can tell it has a terrible connection. No need to disassemble the NES for this, just spray the Kontakt 60 and WL in the switch itself and toggle it around a bit. And you've got yourself another bad contact fixed.
This is the last issue I have found with this NES. It doesn't squeak anymore, the contacts aren't scratching anymore, and most importantly, all games just run right off the bat. This NES and these games have been fully repaired and won't interfere for the next couple of decades probably.
I have learned quite a bit about this aftermarket 72-pin connector that I feel like sharing with the community. Is it any good? Well, I have managed to get it to work fine. It can definitely be used to revive an NES if the connector has failed. But the important thing is that whoever made this connector forgot to lubricate it. Remember that the NES is still 80's technology and the connector has its issues. Nintendo has fixed these in the toploader model, but that was never released in Europe. This connector simply isn't very good by design. This replacement fits excellent on the mechanical side, but the mating force is way too high and the contacts are scratching. Those are serious issues. Contact plating that has been scratched off is permanent damage, and all the plating will be gone eventually. Using tin solder to fix this could work for a while, but tin is a very soft material and not suitable for connectors that need to have a high mating cycle. After lubrication, the contact scratching is gone, the mating force is acceptable and the connection is good, if the game is inserted all the way in. That has always been a thing with the NES. So yes, this is a pretty good connector. But you really need to lubricate it. Also, keep in mind that if your NES connector has bad contacts, you should attempt to repair this first with the steps described above before replacing the connector. Maybe there's no need to replace it.
Also, this game (The Adventures of Rad Gravity) is terribly bad.
Two days after the release of this blog, I realized something. I wrote in the blog that tin plating should not be used for connectors that need to have a high mating cycle. You can clearly see by the color that the motherboard's edge has tin plating. That could work, but wouldn't it make sense to use gold for the games?
Guess what, it does. The games are gold plated. Then what about this replacement connector? I still have one picture that I didn't publish, but it's very useful now.
This is clearly tin plating. Mating gold with tin causes contact fretting. This is a very big fail.
Contact fretting is described in the paper here and another good source is from TE Connectivity here. The original Nintendo connector does appear to have gold plating for the game cartridges, and tin for the motherboard. A very curious design choice and unfortunately some Chinese (probably) failed to notice that or didn't care.
Referring to the TE Connectivity publication, you will get tin oxide transfer from the connector to your games. This is obviously bad and I don't think you can get rid of any tin oxide transferred to get your gold contact area back. Anyone using this connector should stop using it immediately.
This issue has been bugging me for a while now, because I thought I had found a problem without a solution. The 72 pin connector on an NES is flawed by design and the counterfeit Chinese replacement is bad, I learned that a lot of peope referred to it as the 'death grip', which is confirmed. So I thought there was commercial potential here to get a fix developed. Unfortunately, I am two years late.
These guys aren't doing a very good job in online marketing. This solution is hard to find in Europe and that's stupid, considering 1/3'rd of your market is here. But I like this product and the reason for that is that this system eliminates the root cause of the design flaw, which is the push down lever movement. I cannot determine the connector quality from this video, but they claim they've found an experienced manufacturer for these type of connectors. The reviews are all good, and I'm confident that you'd rather have this than the Chinese counterfeit. From what I can tell, this looks to be a good fix and it's not worth competing against. Atleast I know I was right on the commercial potential here. Let's hope I find something new.