benheck's NES 72 pin replacement

[shadow460]

I read somewhere that Ben Heckendorn had used connectors from floppy drive cables to replace the 72 pin connector on the NES. The electrical part is easy to understand, just solder point to point onto the board. Does anyone know how he mounted the replacement, though? I thought he used some kind of glue or epoxy, but I don't know specifically where he mounted it to the locking mechanism, or if he just left the carts to float at an angle.

 

I'm sick of messing with the crap design Nintendo used, and I don't wanna tear that monster down again in another three years to replace or repair the connector yet again, so I'd like to try Ben's way of fixing it.

[Prodos8]

It looks like he glued them to the tilting tray somehow. Here's the link.

[Ian Primus]

That is an interesting hack. The original NES connector is a bad design, for sure - but it can work pretty well if you're careful. I replaced the connector in an NES here several months ago with one of those cheap new replacements. It started out really tight, and a bit finnecky, but now that it's "broken in", it fits more loosely, and works much better. To make your connector last longer, you need to:

 

Clean every game. Never put a dirty cart in your Nintendo. Get a gamebit and disassemble the game, and scrub the contacts with alcohol. When you come home from the flea market with new games, clean them first.

 

Don't cheat. The Game Genie will bend the heck out of the pins in the Nintendo.

 

Avoid leaving a cartridge in the Nintendo when you're not using it. The connector works by spring tension, and leaving a game in there for two weeks can't possibly be good for it.

 

Keep the cartridge door closed except when changing games, and take care of your cartridges - don't leave them on the carpeted floor to attract fuzzies. Anything you can do to keep dust out is a good thing.

 

 

-Ian

[shadow460]

Looks like Ben's mod misses the center pins on the cart, though. If I'm not mistaken, the few games that do have them don't use them. Also if I'm not mistaken, locking the cart down also does nothing save for ensuring contact in the original connector. Actually, no, looking at his pinout, it looks like those center pins go to the expansion port on the bottom. So by using the floppy drive connectors, it'll effectively disable the expansion port. Was it ever even used to begin with?

 

I usually follow the advice given above. Right now the "new" games are on the floor by the unit, but they'll be stored soon. I generally don't leave carts in systems with dust doors or protective sleeves (like the Game Gear), and I'll cover the slots on older systems with something. All my games are cleaned when I get them, no matter what system they are for.

 

Anyway, looks like it's time to dig for some old cables, or go buy a set at the computer shop, and get busy.

 

Oh, now that it's no longer used, the thought has crossed my mind to remove the anti lockout circuit in the one Color Dreams game I have. There is no need to be blasting the system with voltage spikes if the lockout chip no longer functions, is there?

[shadow460]

UPDATE: I tried fabricating the connector Ben used, but the contraption I made fell apart in my hands as soon as I tried a Color Dreams cart on it. It's off to Game X Change to see if they can't sell me another ZIF slot. I know why the one I have isn't working--it's because I can't reach the upper set of pins with anything...and they must have finally gave out.

 

I also want to see if I can find a pinout for that lockout chip and maybe learn how it works. If not, eventually I'll throw in a toggle switch to enable or disable it.

[Ian Primus]

I also want to see if I can find a pinout for that lockout chip and maybe learn how it works. If not, eventually I'll throw in a toggle switch to enable or disable it.

 

			  ---_---
DATA_OUT  <-|01   16|<- VCC (+5V)
DATA_IN   ->|02   15|<- GND
SEED	  ->|03   14|<- GND
LOCK/KEY  ->|04   13|<- GND
UNKNOWN2  - |05   12|<- GND
CLK	   ->|06   11|<- GND
RESET	 ->|07   10|-> SLAVE CIC RESET
GND	   ->|08   09|-> /CPU & PPU RESET
		  -------

 

Here's the pinout.

 

Just cut pin 4 on the chip in the console, and it'll default to key mode. That effectively disables it. You can't remove the chip, because it controls the reset line on the CPU.

 

-Ian

[shadow460]

What I was wondering is if there's a way to disable the CPU reset, though. Currently the only way I know is to cut pin 4. I took the entire pin off of my first lockout, so while I had the NES open tonight I replaced the chip. Pin 4 is now folded up out of the way.

 

However, if there's a way to interrupt the reset after it comes from the chip, then the lockout chip can sit there trying to reset the CPU all day and nothing will happen. You could then leave the chip enabled, which allows an NWC cart to load automatically instead of having to throw a switch on the console itself.

 

I sanded down the original 72 pin unit and put it back in. It works a little easier, but it will have to be replaced soon. I think the part number for the replacement is CX-7800, right?

[Atariman]

Looks like Ben's mod misses the center pins on the cart, though. If I'm not mistaken, the few games that do have them don't use them.

 

This is correct. The pins in the middle of the connector are routed down to the unused expansion port on the bottom of the NES.

[Longhorn Engineer]

If anyone can get this to work I would be impressed. People have tried it on the BenHeck forums without success.

[awace]

What I was wondering is if there's a way to disable the CPU reset, though. Currently the only way I know is to cut pin 4. I took the entire pin off of my first lockout, so while I had the NES open tonight I replaced the chip. Pin 4 is now folded up out of the way.

 

However, if there's a way to interrupt the reset after it comes from the chip, then the lockout chip can sit there trying to reset the CPU all day and nothing will happen. You could then leave the chip enabled, which allows an NWC cart to load automatically instead of having to throw a switch on the console itself.

 

I sanded down the original 72 pin unit and put it back in. It works a little easier, but it will have to be replaced soon. I think the part number for the replacement is CX-7800, right?

acroding to ben hecks page you just leave chip intact then ground that pin4 now do what i always did hold reset wilst powering on and it will stick most times!!!!!!!!!! sometimes i put a dime in reset button to remind myself dont push dime in all way or you have to go get it the holding reset should work..

also just use a blow game genie and solder the connector to the pcb w jumpers so it can wiggle all it wants I did this w my b/w portable seethrew tv on its power input plug its still stock plus jumper wires so the traces can be loose and it still connects..

[awace]

UPDATE: I tried fabricating the connector Ben used, but the contraption I made fell apart in my hands as soon as I tried a Color Dreams cart on it. It's off to Game X Change to see if they can't sell me another ZIF slot. I know why the one I have isn't working--it's because I can't reach the upper set of pins with anything...and they must have finally gave out.

 

I also want to see if I can find a pinout for that lockout chip and maybe learn how it works. If not, eventually I'll throw in a toggle switch to enable or disable it.

you can extract the pins if youre carefull and steal ones from a old nes connecotor then there is a super hard but effective way to hold back and push w super small jewler screwdriver then remove and replace making a part bent in a way that still works but stick down more!!! you might need 3 connectors to do it but its worth it..

[shadow460]

If anyone can get this to work I would be impressed. People have tried it on the BenHeck forums without success.

 

Which one, the expansion port or the floppy connector?

[Longhorn Engineer]

If anyone can get this to work I would be impressed. People have tried it on the BenHeck forums without success.

 

Which one, the expansion port or the floppy connector?

 

Floppy Connector.

[shadow460]

My guess is that they are damaging the pins during the construction. Then again, one set of pins on the traditional 72 pin connector does sit further back. Perhaps what's happening is that the areas the floppy pins sit on have not been "scraped clean" by repeated insertion of the cartridge.

[Prodos8]

If you trim down some of the plastic on an original 72-pin connector (preferably a bad one) you can get the mobo end to fit a cartridge. I have a few bad ones on hand and was planning on using a ribbon cable to connect a couple together, connect one to the mobo and mount the other so I could insert carts from the top into it. It would be a toaster top-loader with perfect a/v. The mobo end is basically a card-edge connector so its not prone to failures like the zif end.

 

[shadow460]

It takes a lot of force to work the mobo end onto the board, though. I'm worried that unless I did do a top loading mod, I would not be able to pull the carts without breaking something.

 

I'll stick to the new 72 pin I got. I don't wanna make it into a top loading console. They can't be stacked like that.

[Prodos8]

It takes a lot of force to work the mobo end onto the board, though. I'm worried that unless I did do a top loading mod, I would not be able to pull the carts without breaking something.

 

I'll stick to the new 72 pin I got. I don't wanna make it into a top loading console. They can't be stacked like that.

Its hard to get off the mobo but slips easily onto and off of carts in my experience. The result would be just as practical as a top-loader but with good a/v. Plus, I have a beater system that would make a good candidate for the mod.

[GOTHCLAWZ]

He made the PS3 laptop, we expect him to be magic.

[Geotrick]

So this happened...

 

https://www.youtube.com/watch?v=2iGRN-Q8kKU

 

https://www.kickstarter.com/projects/113891498/blinking-light-win-resurrecting-your-nes/description

 

http://www.arcadeworks.net/hardware/blw.html

 

I can see a possible flaw in how the end connector is supported. The end groove looks a little weak depending on how much force is needed. They are on the right track though. I would still get one.

[7800fan]

Might be an issue with Game Genie. Galoob did have to issue an alternate version for top loading NES because the original version was hard to insert due to having thicker PCB.

[fujidude]

Avoid leaving a cartridge in the Nintendo when you're not using it. The connector works by spring tension, and leaving a game in there for two weeks can't possibly be good for it.

 

 

I'm not so sure that's correct on that point. Some share your worry about spring tension, some don't. A similar debate took place as it relates magazines for ammunition. As it turns out, there were a lot of people who have "carry" guns that have magazines that were more or less constantly under tension because they were loaded up. Some of them for many years. I say more or less constantly because of the occasional firing practice, cleaning, or what not. Not anyone reported any functionality issues with these. If memory serves, one of the participants in the discussions was a mechanical engineer. He said what wears a spring out the most is compression cycles. That makes perfect sense to me.

[7800fan]

 

I'm not so sure that's correct on that point. Some share your worry about spring tension, some don't. A similar debate took place as it relates magazines for ammunition. As it turns out, there were a lot of people who have "carry" guns that have magazines that were more or less constantly under tension because they were loaded up. Some of them for many years. I say more or less constantly because of the occasional firing practice, cleaning, or what not. Not anyone reported any functionality issues with these. If memory serves, one of the participants in the discussions was a mechanical engineer. He said what wears a spring out the most is compression cycles. That makes perfect sense to me.

 

The springs in the gun magazine are designed stronger for heavy use. NES deck is nothing more than 72 thin leaf springs and it takes just one worn leaf spring to lose connection with the cart connector. But it's more of dirty contact than weak spring that doomed front loading design, there's no rubbing on the pins so corrosion and dirt builds up easily than on cart slots that doesn't use ZIF design. (computer CPU gets away with ZIF socket because most people install it once and leave it for years, no repeated inserting and removal like NES carts)

[fujidude]

 

The springs in the gun magazine are designed stronger for heavy use. NES deck is nothing more than 72 thin leaf springs and it takes just one worn leaf spring to lose connection with the cart connector. But it's more of dirty contact than weak spring that doomed front loading design, there's no rubbing on the pins so corrosion and dirt builds up easily than on cart slots that doesn't use ZIF design. (computer CPU gets away with ZIF socket because most people install it once and leave it for years, no repeated inserting and removal like NES carts)

 

I understand they are much much lighter. The principle is the same though. Leaving a cartridge plugged in that you use most of the time is likely to be less hard on the system than removing the cartridge after each and every use and plugging it back in the next use. That was the idea. I don't have one so this is as far as I'll go with it.