Proposal for HVC-001 Famicom inside a Generation NEX - need lots of tech help!

[satoshi_matrix]

Hey guys. I recently bought myself a Generation NEX Famiclone and I really like a lot of things about it from its general design, 2.4Ghz wireless transmitter and of course its duel cartridge slot design. The only thing I don't like is the NOAC nature of it.

Last year I bought authentic NES CPU and PPU chips gutted from a system and installed them into a hardware Famiclone, converting it into a real Famicom just as 1337Mhz had done before me. This system has been a great way to experience the original Famicom design with AV inputs. I was thinking of that, and then remembered I have a real Famicom with a case in rather poor condition.

That got me thinking of the idea of transplanting the motherboard from that Famicom and into the NEX. Off the bat, I realized it would require significant modifications but I'm rather serious of preforming this mod.

My goal is to have the HVC-001 Famicom motherboard inside the NEX shell, hooked up to both a 60 pin and 72 pin connector, wired to the NEX's existing controller ports, retaining the 2.4Ghz wireless controller support, and building a small video amplifier so I could use the NEX's existing composite jacks and hopefully replace the Famicom's entire daugherboard.


Before I can attempt anything though, I need to understand the Famicom motherboard in much more detail that I currently do. This is where I'm hoping you guys can help. I've taken many high res, clear and vivid pictures of my Famicom's motherboard in the hopes that the component and connection points can be identified for my purposes.

General things I'd like to know:

1. Is what I'm purposing even possible? In other words, can you solder wires from a Famicom's 60 pin solder joints to a 72 pin connector and simply leave the additional 12 pins floating and expect NES games to work off a Famicom? If I recall, the additional pins were used for the NES-10 lockout chip and the unused expansion port, both of which are irrelevant on the Famicom. So basically, is my idea sound?

2. One of the big concerns is fitting everything in and having it stay in place. Without being able to screw the Famicom motherboard in place, is there some kind of glue or epoxy that would be able to secure the board to the button plastic without damaging the motherboard?

3. What is the best way to desolder the 60 pin connector off the Famicom? I'm hoping a solder sucker and soldering iron could do the job?


Okay, so here's detailed pics of both the Famicom and the NEX motherboards. If you guys need more pics, just ask and I'll post em. Feel free to edit these pics with labels if you can!

Entire motherboard
http://www.flickr.com/photos/30701966@N04/5437632711/sizes/l/in/photostream/

for the power switch, which wire is power and which is ground?

Chip side of the motherboard, upper
http://www.flickr.com/photos/30701966@N04/5438240718/sizes/l/in/photostream/

Chip side of the motherboard, lower
http://www.flickr.com/photos/30701966@N04/5438239666/sizes/l/in/photostream/

I need to know the controller pin outs for the connectors on the front of the system so I solder wires to the solder joints and signal them to the NEX 7-pin NES controller ports. I'd also like to know the DB-15 pinout. Ideally, I'd like to incorporate the DB-15 port into the NEX along with the two controller ports, just like in the AV Famicom.

Daughterboard and ribbon connector
http://www.flickr.com/photos/30701966@N04/5437635431/sizes/l/in/photostream/

What are the seven lines that lead from the motherboard to the daughterboard along the ribbon cable? Leading to the daughterboard, I see (from the left) the second is VCC, the fourth is marked +B, and the sixth is marked G, which I'm assuming means ground.

If I were to guess this looks like it carries power, ground, video and audio signals, but I need to know exactly what each line actually does so I know how to wire it for the mod.

Solder side of the motherboard
http://www.flickr.com/photos/30701966@N04/5438242666/sizes/l/in/photostream/

Solder side of the motherboard, upper
http://www.flickr.com/photos/30701966@N04/5437638029/sizes/l/in/photostream/

Solder side of the motherboard, lower
http://www.flickr.com/photos/30701966@N04/5438243540/sizes/l/in/photostream/

In the bottom right, just above the screwhole are four solder points for the Reset button. I'd like to use the NEX' reset button. What are these four solder points pinout for lack of knowing what to call them?


Okay, so moving on, here's high res pics of the NEX boards.


chip side (globside?) of the main daughterboard.
http://www.flickr.com/photos/30701966@N04/5438302644/sizes/l/in/photostream/

From what I can tell, this board supplies the connection to both controller ports, contains the wireless controller transmitter and carries unamplified video/audio signals to the composite outputs.

From left to right, the white connectors are 5 wire Video/Audio, 7 wire controllers (?) and 2 wire LED power light for wireless controllers.

On the far right are 12 connectors for the NES 7pin controllers, but Messiah labeled them extremely strangely.  Can someone please help translate what the inputs are in the general terms of Clock, strobe, data, +5v, GND?

LED is not even connected, so ignore this.
VCC = +5v for both controllers (?)
GND = GND for both controllers (?)
CK2 = Clock for Player 2 (?)
D1 = ?
PD4 = ?
PD3 = ?
EN = ?
CK1 = Clock for Player 1 (?)
D0 = ?
S0K2 = ?
S0K1 = ?

Solder side of the main daughterboard.
http://www.flickr.com/photos/30701966@N04/5438303472/sizes/l/in/photostream/

The wires leading to the left go to the Player 1 and 2 7pin NES controllers. The white 4 pin connector goes to the main motherboard, but I'm not sure what the lines are. I'm assuming two must be for VCC and GND, but no clue about the other two. The wireless transmitter is in the middle of the daughterboard.

Chipside of the main motherboard, left side
http://www.flickr.com/photos/30701966@N04/5438306632/sizes/l/in/photostream/ and http://www.flickr.com/photos/30701966@N04/5438307292/sizes/l/in/photostream/

Anyone have any idea what the cable closest to the 60 pin connector is? As you can see, the inputs aren't labeled at all.

Chipside of the main motherboard, right side
http://www.flickr.com/photos/30701966@N04/5438308102/sizes/l/in/photostream/

Not much to ask here except which wire is power and which is ground for the power supply jack. I've totally forgotten this since highschool. 

Solder side of the NEX motherboard
http://www.flickr.com/photos/30701966@N04/5438309606/sizes/l/in/photostream/ and http://www.flickr.com/photos/30701966@N04/5438310428/sizes/l/in/photostream/

Solder side of the NEX Power and Reset daughterboard
http://www.flickr.com/photos/30701966@N04/5438305868/sizes/l/in/photostream/

The left is the Reset button, the right is the Power button. It is connected to the controller daughterboard through a four wire ribbon cable. The leads are marked as RES, GND, 10V and 10V again? I don't get it. Can someone explain this please?

The NEX's 72 pin connector
http://www.flickr.com/photos/30701966@N04/5437702545/sizes/l/in/photostream/

According to a lonngggggg nesdev thread, miswired, but I don't know enough about it to see where/how. Would I have to replace the connector entirely if I wanted MMC5 game support or is it just a problem on that red circuit board that I'd be scrapping? What about the NEX's 60 pin connector? Could I desolder it and expect it to work correctly with all Famicom games on a real Famicom?

Okay, well I think that's enough writing for a single post. Hopefully I can get enough info to get started.

[tappybot]

You don't have Dr. Wiley as your avatar for nothing!

I know virtually nothing on the subject, but the project sounds interesting and I wish you goodluck. 

[Xious]

Hm.. I'll post a bit for now, and edit this later to expand, hopefully covering all of your questions.

As with anything of this nature, the word 'impossible' shouldn't even be considered.  The main decisions you'll need to make are if you are up to the tedious nature of this task, and how much you are prepared to spend on the project. You will also need a 72-pin female edge connector to do this, and it needs a 2.50mm pitch: Standard 72-pin edge connectors have a 2.54mm pitch, which renders them unsuitable. The additional pins are for the 10NES chip, and ten are for the EXP routing; the NES slot also lacks audio in/out pins that are present on the FC slot. You do not need to wire the additional lines, as they'd have nowhere to go.

You can use hot-glue to secure the guts: Nothing is going to just screw down nicely though.. I advise not using any form of solvent-based adhesive; do not use epoxy for this, as one error = ruin. All of the diagrams that you need including the joystick connectors are in the NESDev archives & wiki. The seven lines are audio out, video out, ground (x2),+5V in, +5V out, and unregulated voltage.

For large connectors and components (through-hole), pick up a de-soldering iron (or an electronically heated solder pump), and a temperature regulator station; the latter especially for ICs.

I suggest tracing back the ports on the EX with a circuit checker: Compare each hole in the female port to the connection on the logic board, then look-up the diagram for a 7-pin Nintendo controller port. This way, you are positive that it is correct.

[satoshi_matrix]

You will also need a 72-pin female edge connector to do this, and it needs a 2.50mm pitch: Standard 72-pin edge connectors have a 2.54mm pitch, which renders them unsuitable.

what about reusing the existing female 72 pin connector already present on the NEX?

pics:

http://www.flickr.com/photos/30701966@N04/

the red mobo pics are all NEX pics.

[Xious]

Indeed: That's what I would advise, as if you don't need to worry about using the NEX system for NES titles again, then it would mount up inside the case perfectly, and you don't even have to remove it from the PCB. I suggest removing the ribbon cables, or unplugging them if they have box headers/Molex connections, and using them to make the bridge to the FC slot.