My twin famicom with every upgrade imaginable.

[Drakon]

Since I've gained good experience building systems for other people I decided to pull my twin famicom out of the closet and have a bit of....fun with it.

I added the following to my twin famicom:

True RGB and s-video (using the crystal clear sony cxa2075 encoder), amped "stereo" sound with bass boost, replaced the rf jack with a s-video jack, replaced the unused B port with a n64 multi av port, added the ability to use a powerpak with the rgb setup.  No holes were cut in the case I just desoldered unused ports to install all the ports I'd need.  Also both the ppu and the rgb compatibility chip are socketed in fully connected precision sockets so it's very easy to restore the system back to running with the default composite ppu.

Pictures:





















The audio wiring was extremely tricky.  It was difficult locating the traces that connect pins 45 and 46 on the cartridge connector (you need to disconnect these for the audio circuit to work).  Also the audio circuit didn't sound as good as my av famicom (the circuit is designed for the av famicom).  I fixed this problem by cutting the traces from the audio pins on the cpu and rebuilding the first chunk of the audio circuit based on the famicom diagram.  Rebuilding the first section of the audio circuit (4 resistors) made the audio in the twin famicom identical to my av famicom when wired into the audio upgrade kit.  Also building my own audio circuit made it so the system no longer mixes in the audio from the microphone on the second controller which is wonderful.  I'm guessing that the fds upgraded audio chip is also disconnected but normal audio from the fds works fine.  I can always wire up a switch later that will let me switch between my custom audio circuit and the original audio path.

[turkishproverb]

That is glorious.

[Drakon]

That is glorious.

Thanks.  I've already come up with the next step.  I plan on desoldering the existing famicom db15 expansion port.  Then I'm going to see if I can mount a standard db15 in its place.  If I can install the standard db15 and be able to plug things into it then I'll build an adapter from the standard db15 to two nes controller ports.  I'd also build an adapter from the standard db15 to the famicom one incase I ever want to use famicom addon....stuff

[Frank_fjs]

Sensational!

So the B port is now where you get RGB from, via a SNES SCART cable? What is that port usually for anyhow, in stock form?

All that modding and no power LED though, shame on you.

[Drakon]

Sensational!

So the B port is now where you get RGB from, via a SNES SCART cable? What is that port usually for anyhow, in stock form?

All that modding and no power LED though, shame on you.

Yes the b port now outputs rgb, s-video, and amped / bass boosted stereo sound.  The port that used to be there is one of those unused ports I double checked with satoshimatrix about it first.  I didn't bother with a power LED because when I build stuff I try to keep it as factory looking as possible.  I still have yet to cut any holes in the case and I don't think I'll have the need for that.

[ericj]

Thanks.  I've already come up with the next step.  I plan on desoldering the existing famicom db15 expansion port.  Then I'm going to see if I can mount a standard db15 in its place.  If I can install the standard db15 and be able to plug things into it then I'll build an adapter from the standard db15 to two nes controller ports.  I'd also build an adapter from the standard db15 to the famicom one incase I ever want to use famicom addon....stuff

Instead of this, why not build a DA15 to standard DB15 port, that way you can preserve the port already in the Famicom?

Or, you could also just use two of those cheap NES extension cables and wire them up to a DA15 female plug and pass through the male section of the DA15 cable so you can utilize the DA15 port if you need it for a controller.

[Drakon]

Instead of this, why not build a DA15 to standard DB15 port, that way you can preserve the port already in the Famicom?

Or, you could also just use two of those cheap NES extension cables and wire them up to a DA15 female plug and pass through the male section of the DA15 cable so you can utilize the DA15 port if you need it for a controller.

That would be a great idea if you could find cheap da15 female ports.  But I didn't find any.  Anyway it's all done and works perfectly.  I verified with someone else who's done this mod that this schematic is the correct one:



It indeed is it worked perfectly first try with both controllers.  I'll take pics once the digital camera battery is recharged.

[ericj]

Tototek sells the DA15 cables for around $9 shipped--since they're extension cables you get both the male & female ends. I've used that schematic before, so I can also verify it works.

[Drakon]

Tototek sells the DA15 cables for around $9 shipped--since they're extension cables you get both the male & female ends. I've used that schematic before, so I can also verify it works.

*shrug* I just like making things use super common ports.  Anyway here's the pics:







I havn't made a box for my controller adapter yet 
Post Merge: February 28, 2012, 11:07:17 am
Audio wiring is 100% finished.  The internals of this machine are 100% done now:





Unfortunately if I wire both the default system audio out and the kit audio out into the same connection the default audio out doesn't work.  So when I switch between the two I need to move the rca audio cord to the back of the system.  It's a minor annoyance but it's better than having to install another switch.

[CkRtech]

Drakon -

I really admire a lot of the work you have done on these machines. I haven't personally touched my sharp twin famicom since I did a quick and dirty controller wire-up test back in (holy cow...) 2007 - http://www.famicomworld.com/forum/index.php?topic=1559

That thread was quickly hijacked. Ha!

I am quite interested in the work you have done on this Twin Famicom for several reasons. I have been wondering if it was possible to create the one (Famicom) machine to rule them all - Disk support, Japanese games, U.S. games, external controller connections, etc.

AND

It would also have video output superior to composite - in the very least a clean S-Video output - and optimally RGB output. The first time I looked into this, the Playchoice 10 PPU-rip option was the only item available, and it didn't quite seem to be without some problems.

So here I am again - years later - wondering what had possibly surfaced. I saw your work in your forums (mostly with the AV Famicom) and found that exciting. Now I see this thread, and I have to figure that this is the route to go for the ultimate machine.

As I understand it, that kit (that uses the CXA2075) contains some intricate work with everyone's favorite activity - surface mount soldering? Not for the faint of heart. I also saw that some of the trace work was a bit annoying.

What sort of difficulty would you give this one? 9/10? I believe anything is possible with patience and the right tools & temperature, but man...

Anyway, again - Thanks for sharing this. Great work.

[Drakon]

Uhh the kit comes with a cxa1645 but I upgraded it to a cxa2075 it's a drop in replacement.  The difficulty all depends on how good you are with soldering.  Unfortunately the audio circuit on this kit is specifically designed for the av famicom so it's hard to get it sounding exactly like the av famicom unless you disconnect the ppu audio traces and wire up four resistors and...it's basically a mess.  And even after doing that mod it won't sound 100% like the av famicom.  Also I find that I prefer the default audio of the av famicom over the default twin famicom audio.  Really I think the av famicom is the ultimate version and you can play fds with a fds, a ram cart with the fds loadr pc cable, or a powerpak emulating the fds works great too.  Also the rgb and s-video from the twin famicom won't be as good quality as the av famicom because these rgb ppus lose signal quality even if the rgb travels a few extra inches before connecting to the kit.  Also the pcb design of the twin famicom isn't as good as the av famicom so there's a little more interference with it.  The two best models in terms of video quality are the av famicom and the nes 2.  But the nes 2 suffers from the same audio wiring issue as the twin famicom.  I use the playchoice ppu and I fixed every problem.  I even romhacked a game that didn't use the rgb pallette properly to use it correctly.

[CkRtech]

I suppose the other thing to worry about is acquiring the RGB PPU.

Have you used several different types in your mods or do you stick with a certain one (RP2C05, etc)? I guess they are hard to come by so you gotta use what you can find.

Did you order your kits directly from http://homepage3.nifty.com/F-LABO/ProductsList.html ? Looks like I would have to google translate it and hope I fill his form out correctly. Ha!

[Drakon]

I suppose the other thing to worry about is acquiring the RGB PPU.

Have you used several different types in your mods or do you stick with a certain one (RP2C05, etc)? I guess they are hard to come by so you gotta use what you can find.

Did you order your kits directly from http://homepage3.nifty.com/F-LABO/ProductsList.html ? Looks like I would have to Gawagle translate it and hope I fill his form out correctly. Ha!

I've used the rp2c03b and the rc2c05-04 chips.  But the 04 chip you need to build an extra circuit to get it to work on a nes / famicom.  I don't order the kits directly from the seller I use a proxy company to get them out of japan.

[famiac]

That site is amazing! what do they sell? Kits for mods? i used google translate but to no avail. Im learning japanese but i don't know kanji...

[CkRtech]

That site is amazing! what do they sell? Kits for mods? i used Gawagle translate but to no avail. Im learning japanese but i don't know kanji...

I find that the easiest way to translate these days is to just paste the URL in google, search, and then hit translate.

Drakon - do you have a proxy you recommend?