PoC Front Loader to Top Loading Mod

[Karatorian]

I've been thinking about this idea for a while as my NES was extremely unreliable. As a friend of mine bought me a Famiclone for Christmas, I decided that it was finally time to risk it.

So here's what it looks like (at the moment):

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From this close-up, you can (almost) see how I did the mod:

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The top side of the mother board:

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The bottom side of the mother board:

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Not the prettiest soldering job, I know, but it does work. Well mostly.

I tested it with Tom and Jerry, Mag Max, TMNT, Excite Bike, Little Nemo, and SMB/Duck Hunt. Everything but the SMB/DH multicart worked. That one works on the clone. (But for some reason wasn't working on the clone when I first tried it a few days ago, so it might be flaky.) I haven't tested it with the other two games I own (Final Fantasy and Dragon Warrior), because I'm worried that something is wrong with the mod and could damage them.

Any idea as to what could cause the SMB/Duck Hunt cart and none of the others to fail? I'm tempted to bypass the NES's CIC and see if that fixes it, but that seems like a bit of an unjustified stab in the dark.

I haven't even started on modding the case for this. I think I'll make a full custom one, because the way it currently is, you have to put the carts in backwards, so I'll probably spin it around. Also, the edge connector is at a little bit of an angle, so if I mount the motherboard off kilter, I can correct for that as well.

Any thoughts, comments, flames, or other input you have would be greatly appreciated.

[l_oliveira]

Actually NES cartridges were designed backwards so the label would face up while the cart is inserted on the system...

Why ? So they would match (design wise) the shape and circuit patterns of FAMICOM carts. If you open an FAMICOM cart made by Nintendo the chips inside will be facing the back sticker, not the GAME TITLE label. So when you place it on a pin adapter on your NES, the GAME TITLE label sticker faces down but the chips inside the cartridge will be facing the TV SET, as would an actual NES cartridge.

Just same as with the Super NES, where the chips inside the cart are aways facing the TV set direction.

I don't think it justifies or is worth the trouble you make an complex wiring just to flip the connector in a way you can stare to the cartridge label while playing.


Nice mod btw. 133mhz did something similar but his mod the cart would connect straight to the board, not in 90 degrees.

[infiniteneslives]

I don't think it justifies or is worth the trouble you make an complex wiring just to flip the connector in a way you can stare to the cartridge label while playing.

I think he was saying just flip the entrire mobo assembly around since he's making a custom case.

Any idea as to what could cause the SMB/Duck Hunt cart and none of the others to fail? I'm tempted to bypass the NES's CIC and see if that fixes it, but that seems like a bit of an unjustified stab in the dark.

Are you sure the carts not dirty or just a connection issue with that game? I doubt it's that title specifically thats the problem.

For what it's worth an alternative would be to just make your own rigth angle double female connector out of some 72 pin connectors from digikey. I know there is a pitch difference, and some may disagree that it works, but I made myself a 180 connector out of em and love it especially for the prototyping work I'm doing since the cart doesn't have to get pressed down you just pop it in and it works.



More info, part numbers, and pictures in this posthttp://nesdev.com/bbs/posting.php?mode=quote&p=80126

[Karatorian]

I think I figured out the problem, and it's not good. I almost positive it is the SMB/DH cart that was the problem. Looking at it, I noticed that the edge connectors on the back of the PCB where weird. Something like this: http://bootgod.dyndns.org:7777/profile.php?id=244

Checking all my other carts, the only one that was also like that was the Dragon Warrior cart. When I tried it, it didn't work either. This is starting to make sense, as that's the only other cart to give me trouble in the Famiclone as well.

I think the problem is that when I hacked up the 72 pin connector, I used motherboard half, rather than the cart half. I had good reasons for this. The cart half didn't connect reliably, and wasn't very stiff. Unfortunately, the cart I used to test the whole idea before I made destructive changes had full length contacts on both sides. So, now I think my edge connector is too short.

I'm not sure what I'm going to do at this point. It's not really much of a loss, as at least now my NES can play most of my games. (Before, I could barely get it to boot anything, nevermind consistently.)

I'm thinking I might try what infiniteneslives suggested and build a ninety degree female to female connector. Only downside is I'll have to clean up the mobo edge connectors. (I knew I bought that solder sucker for a reason...)

So, does anyone have any insight as to what's up with the short connectors? Was it some sort of anti-pirate measure, or something else?

[3gengames]

A clean game and connector and you should never have any problem, but kil the CIC anyway, it serves no purpose today. And push the game down is a joke, it only hurts your connector. Don't do it.

[Memblers]

Another old trick is to use a Game Genie connector for "back-loading" like this: http://arstechnica.com/old/content/2003/02/nintendo.ars

Of course, it's easier now to just buy a replacement connector.

[Karatorian]

Speaking of Game Genies, before I got the Famiclone, I used a GG to make my NES more reliable. The GG stuck in the flaky connector pretty well, so once I got it tweaked just right, I just left it in there and could swap games.

The GG does have a nice connector, but I'd kinda hate to cannibalize it.