FamicomBox+ Disassembly & Installation Guide

Disassembly & Installation Guide

Currently this guide is under construction and will be updated when the FamicomBox+ mod is launched in the future. 

Tools Needed

To remove the Famicom Box cover, you’ll need the keys for both the coin box (if fitted) and the front panel. The Famicom Box uses a proprietary screwdriver, originally supplied by Nintendo. This tool is rare and expensive, as shown below:

Tip: An E8 inverse Torx bit fits the screws well enough to remove them, but it isn’t a perfect match. Be careful not to strip the black coating on the screws.

Disassembly

1. Unclip and slide out the power supply (two clips hold it in place).
2. Remove all 16 proprietary screws from the unit’s exterior.
   
3. Use both keys to unlock the front cover.
4. Lift the top cover straight up.
5. Remove the two screws securing the grounding cables.
   
   
6. Remove two screws from each metal bracket, then lift out the bracket that held the power supply.
   
   
7. Remove the plastic clip that secures the motherboard in the base (see previous image).
8. Unscrew all six screws holding the black cartridge cages.
   
   
9. Lift away the back panel, disconnecting the large ribbon cable and the small connector as you go.
   
   
10. Disconnect the small ribbon cable from the logic board and slide the board out of the housing.
    
    
11. Lift the cartridge connector assembly and remove all 24 screws holding the metal bracket and the three cartridge housings onto the board.
    
    

Build & Installation Guide

This section covers building and installing the FamicomBox+ Mod. Some steps may still be evolving as the mod improves.

SSS-SOB-REPRO Board

The SSS-SOB-REPRO board replaces the original Famicom Box front board. Because of significant cartridge slot changes, it’s easiest to swap the whole PCB rather than modify the old one.

Connector Note: Cartridge connectors from AliExpress are slightly different in size, which may prevent some games from working. To address this, cut off the mounting wings from each connector and raise it 1mm from the PCB. A 3D-printed alignment tool is available to help with this.

Otherwise, all other components are soldered in as normal.

Finished Board (Front):

Back:

FamicomBox+ Board

When assembling the FamicomBox+ board, pay close attention to IC11. Solder the mounting pins before the IC socket, and ensure all pins are perfectly soldered on the underside for a good fit.

Finished Board (Front):

Back:

Installation: Step-by-Step

Part 1

• Remove several components from the Famicom Box logic board and install IC sockets. For each IC, it’s best to desolder, fit a socket, and leave the original pin disconnected. This makes it easier to revert to stock later.
• IC5E (3198 CIC chip): Lift Pin 4 to enter “Key mode” and disable security.
• Remove these ICs:
  • 2Y (disconnect Pin 1)
  • 4Y (disconnect Pin 18)
  • 4S (disconnect Pin 26)
  • 4J (disconnect Pin 15)
  • 5E (disconnect Pin 4)
  • 6N, 6L, 6K, 6H (do not refit these ICs)
• Desolder the PRG ROM from the menu cartridge (fit an EPROM in a socket for easy programming).
• Desolder the 72-pin cartridge connector.

Part 2

• Isolate the pins from the 72-pin connector and resolder it onto the logic board.
  
  
• Isolate these pins:
  • 15 (IRQ)
  • 21 (PPU /RD)
  • 38 (M2)
  • 57 (CIRAM /CE)
  • 58 (PPU /A13)
• Optional for future mods: Disconnect these pins: 16, 17, 18, 19, 20, 55, 54, 53, 52, 51 (EXP0–EXP9).
• Install wiring: Crimp five wires onto pins 1–5 of the 10-pin ribbon connector, linking the Menu Cart and Mod Board as follows:
  • 1 (M2) – Pin 38
  • 2 (IRQ) – Pin 15
  • 3 (CIRAM) – Pin 57
  • 4 (PPU /A13) – Pin 58
  • 5 (PPU /RD) – Pin 21

Part 3

• Plug the mod board into the main logic board and wire up the 14 solder points on the right side of the board, plus the EXP Audio line.
• Stick down self-adhesive standoffs when installing the mod board for support.
• The mod board plugs into four IC sockets—double-check pin alignment.
• Tip: The labels on the mod board and this reference image can help with cable placement.

Part 4

• Create three 26-pin ribbon cables (about 30 cm each).
• Install the SSS-SOB-REPRO board: fit the three large black plastic sections, plug in the LED connectors, and secure the large metal bracket.
• Mount everything back into the Famicom Box housing and screw it in.
• Slide the logic board back into the housing. Solder the two audio cables to Cart 1 and Cart 14 (audio pin is marked):
  
• Plug in the three ribbon cables. The mod is nearly complete.

Part 5

• Screw the power supply and rear panel back onto the Famicom Box.
• Leave the top case off—you’ll need access to calibrate the audio if using expansion audio.

Flashing the Menu EPROM

Update the menu software to work with the FamicomBox+ mod. If you haven’t already, de-solder, erase, and reprogram the EPROM with the provided PRG file.

If your Famicom Box boots with a loud beep and a flickering display, the menu isn’t loading—this usually means the mod or the menu software needs troubleshooting.

The final install should look similar to this (this example also has an NESRGB installed, which isn’t required for this mod):