Has anybody modded NES controller ports to teh front of a Famicom before?

[P]

Probably possible but personally I have no interest in doing any mods that removes any features. The point of my suggestions were only to add features of the NES to the Famicom without loosing any existing features. And loosing the keyboard just to add Four Score and whatnot would be out of the question (and I believe it is one of the more popular peripherals, not one of the unpopular ones).

All my suggestions are highly theoretical though, requires a lot of work and probably introduces a bunch of new problems to solve. It might be easier to use a New Famicom that already has the NES controller sockets, connect $4017.D3/D4, build the extra hardware needed for the $4016.D3/D4 (as required to use two Zappers) and build the microphone hardware.

[relo]

Just did some testing, the only points that's missing, a direct connection, on the expansion port from the internal controller ports is D0(1) and audio. Considering I don't think most peripherals use the audio port, beyond possibly some karaoke stuff, I think disconnecting that to connect D0(1) might be the best option while leaving nearly everything intact.

And considering passing through audio from the controller port is not that important I feel, as that's rarely used. (10 games or so, right?)

At any rate, I'll try it in the near future and see what comes of it. I recon it's only cutting the audio connection, wire up the D0(1) and wiring up the neo geo extension cable to the four score. All that is of course assuming controllers are used the same across both the NES and famicom. And considering my quick and dirty attempt that lead me to this forum of just hooking up the four score using the "nes to famicom adapter" image from 2008 that uses D1 instead of D0, it has decent chance of working I feel.

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Edit:
Making it so I get D0(1) on the expansion port made it all work. It essentially hijacks the internal controllers completely (read, once fourscore is plugged in only the mic on player 2 works) and only makes the controllers put into the fourscore usable. Only issue I currently have which I'll later figure out is when the internal Player 2 controller is plugged in no player 2 controller works either on the fourscore or internal. But once the internal player 2 controller is plugged out the fourscore is fully functional and works with games supporting the fourscore as far as I've tested. So now the task of figuring out why player 2 doesn't work when the internal player 2 is plugged in (except mic). Probably some minor thing to get player 2 fully functioning or in an extreme circumstance a switch to disconnect the connection that makes the internal player 2 port not being able to use any player 2 port.

Or in simple terms, fourscore fully works on the famicom if you unplug the internal player 2 and add D0(1) to the expansion port. I'm looking at getting the internal player 2 being plugged in to not mess with anything.

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Edit 2:
Reason is something with the D0(2) line. The obvious but also brute force solution is a simple switch on that line (orange wire), but I'll see if I find a more elegant solution.

[P]

Considering I don't think most peripherals use the audio port, beyond possibly some karaoke stuff
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And considering passing through audio from the controller port is not that important I feel, as that's rarely used. (10 games or so, right?)

No, the karaoke set has its own microphone hardwired in the cartridge. The audio pin in the expansion port is an output pin (apparently it's without expansion audio mixed in on the original Famicom while it is mixed in on the New Famicom). Only peripherals that uses it are things with a headphone port, like the S.D. Station or certain external controllers. No games so far relies on it as far as I know.

Making it so I get D0(1) on the expansion port made it all work.
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fourscore fully works on the famicom if you unplug the internal player 2 and add D0(1) to the expansion port.
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The obvious but also brute force solution is a simple switch on that line (orange wire), but I'll see if I find a more elegant solution.

By doing that you gain the Four Score but looses external controllers (plus probably a ton of other peripherals relying on it). If you can put a switch that disconnects the internal controller socket and connects D0 to the expansion port you could avoid having this conflict and possibly retain the original features.

[relo]

Good to know that cutting the audio line doesn't really effect the functionality of the console.

You don't need to disconnect the whole socket for it to work, just the D0(2) line. My suspicion is that that line is simply pulled out of spec making it unreadable for the famicom so possibly a passive component in the controller or fourscore could fix that. But it's 4AM right now, so going to check that tomorrow if my work room isn't an oven.

I'd personally rather have a switch as a last resort, but if someone needs this mod now a switch on the orange wire (D0(2)) in the second player controller does the trick (or you could do it in the console, but I feel in the controller it would be more elegant). I like my mods to be more passive, so I'll check if that's possible within my knowledge.

[P]

I meant a switch for both D0 lines so that external controllers and headphones can be used again.

[relo]

Headphones? You mean the mic? The mic can always be used as long as the second internal controller is plugged in, circuitry is completely separate from the normal controller circuitry.

Or do you mean in the famicom itself so you can re-enable the audio line on the expansion port? Then it would probably be smart to use a dual pole single throw switch to do so. Essentially a switch with "stock" and "four score compatibility" modes. Though I imagine most people wouldn't mind losing the chance to use headphones on a famicom or a speaker in a controller to gain the use of regular NES controllers and fourscore compatibility.

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Edit: It might be my PAL NES stuff but D0(1/2) both get pulled high to 5V when the fourscore is attached but normally is ~.25 with just internal controllers. Considering I don't have NTSC NES stuff I can't be 100% sure. At any rate the high 5V would be a good way of detecting if the fourscore is in use, as I don't believe that's normal behaviour. Unless someone can test with a peripheral that uses D0(2) on the expansion port.
If regular D0(2) usage on the expansion port also gives ~.25V then the pulling high of the 5V line could be used as detection system on a pic chip. (and then we'd need to find someone that can write code for a pic chip) The mod might be different or even simpler on NTSC\SCN PAL fourscore hardware. As from what I've read those don't pull high, so for those I suspect that the mod as is is good enough without switching circuitry.

[P]

I meant the audio output in the expansion port that you used. Since your mod breaks things, a switch to undo the mod is in order while also getting rid of the conflicting problem.

It's not about if people want headphones or not, it's about the fact that the mod is intrusive and changes the specs. That's a surefire way to make it incompatible with other mods or accessories.

[relo]

Considering the audio line is at an end of a trace breaking other mods isn't much of an issue, unless some mod specifically relies on getting audio from that pin instead of the nice solder pad named sound connected to the same trace and thus gets the same data. Nor is that pin normally pulled down for anything so for the famicom it's lust like there is no peripheral attached to that pin that would use it. So I'm not worried about it breaking other mods.

And as the pin only caries audio out, which only function is as an audio output, I'm not worried about losing that either. I understand people that want to keep everything as unobtrusive as possible though for things like headphones.

I'd just be happy to have the fourscore working fully without a need for a hard switch. If that means I don't have audio output on the expansion port I'm fine with that, ideally I wouldn't lose that but I won't go out hunting for a more complicated solution as the audio port has such a limited use and personally wouldn't miss it for a second, nor do I think the average "I just want to play games" user would miss it. And looking for such a solution quite possibly would make the mod a lot harder to perform, to troubleshoot and harder to undo if one wishes. For me it's one of those "I'd be nice if I also could get that" situations.

Though like I stated before, a single dual pole single throw switch is a solution for those people that want to have a stock mode and a four score mode.

My current way only of doing things as I've set up only trades the chance of using peripherals that use the audio out like the headphones so you can fully use NES controllers on your famicom, get turbo functionality on those controllers including controller 1 and 2 and allow you to play 4 player games that aren't exclusive to Japan with that functionality (most interesting games from that group have already been modded for use with a four score anyways I believe). I think for the vast majority of people that's a fine trade and there is a solution so you shouldn't have to make such a trade.

That said I'd love to get a full list of peripherals that use that pin, because I honestly can't think of much use for it beyond headphones and speakers.