Luckily the Famicom has that front controller port, which leaves a lot of options. I went with the adapter option. An adapter that would let me use my NES controllers on the Famicom. It came out so great I thought I would share.
edit: Not the same adapter, but here's an inside pic of a virtually identical one I made:
I used small zip ties to prevent you from being able to pull the wires out. After this pic was taken, I also used a liberal amount of hot glue so you can't push the wires in either.
/edit
I wired it according to the diagram posted by 133MHz on the Famicom World forums:
http://www.famicomworld.com/forum/index ... pic=3583.0
I decided to put it in a little project box from Radio Shack for a nicer appearance, I even had some grommets on hand for a real professional look.
Any one could make this, it's very easy. You don't need the project box, and you don't need to know how to solder. If you can strip and twist wires together, you can make this adapter. All you need is one (preferably two) NES controller extension cables and a Famicom (or NeoGeo) controller extension cable.
Best part is, you could substitute parts if you can't find them. For example, if you can't find a Famicom, NeoGeo or NeoGeo CD (all the same thing) extension cable you could just use the cable from a broken controller from one of those systems (as long as it has all the pins/wires you need need). Hell, you don't even need the Famicom extension cable if you're desperate. You could hard wire a NES (or two) controller to the console, or you could hardwire the NES extension cables to the Famicom.
edit: I like to expand on this "hardwire" idea a little more, for any on interested in doing it. Get two NES extension cables from the Racketboy store, eBay, Amazon, etc. You'll be cutting off the male end (the end that you would plug into a NES console). Cut it to the desired length of course. You may want just 6" of wire hanging out the back of the console, or you might want 3' or the full length of the cable, it's up to you. Use the diagram in the above link for the Famicom's front port. You can solder the NES extension cable's wires to the corresponding pins on the Famicom's PCB, then route the wires out the back of the console where the Famicom's controllers usually go. Additionally, where the Famcom's controller's plug in on the motherboard, I believe you can solder the NES extension cables there too (as alternative points).
Knowing what I know now, if I bought a Famicom and wanted to use NES controllers, this is what I would do (just route the NES extension cables out the back where the Famicom controllers usually go) instead of having to buy the Famicom/NeoGeo cable. It's the cheapest option, and it's just as functional as the adapter.
edit #2: I found this guide on the net for any one interested in doing this. Hopefully with this guide plus the info in this thread, it should be a fairly simple affair: http://www.1up.com/do/blogEntry?bId=8490331
edit #3: Another thing that's worth noting: If you use a FC/NeoGeo and two NES extension cables to make this adapter, you can use the opposite ends of each cable to make a second adapter of the opposite purpose (ie: Use FC controllers/accessories on a NES console). The first adapter I made, I actually sold the other ends of the cables to a Racketboy member so he could make that adapter for himself. He had some sort of FC controller that he wanted to use on his NES and was very happy to be able to make this adapter. So don't forget, the ends of the cables that you don't use aren't worthless, don't throw them out! Either sell them to some one that wants to make that adapter or make that adapter yourself and sell it.
In addition to that, the ends of the NES cables that you aren't using could also be used to repair controllers with damaged wires.
/edit
Other ideas I had before I made this adapter was to just get a Famicom 3rd party controller. There's plenty of them, like this one:
Or better yet, this one:
I really like that Hudson Soft controller for a few reasons. One, it would keep the color scheme of the Famicom. It even looks like a first party Famicom controller. Two, the wire is coming out of the top of the controller (as oppose to the side). And three, it's a turbo controller too.
There's also the Hori Commander controller.
So there it is, all the options I explored for an alternative to the hard wired Famicom controllers.
