This is a way to convert Nintendo Famicom (early model) into video output. Before making this modification, the video board must be assembled. If you haven’t, please assemble it here.
- Tools required for work
- Removal of Nitendo Famicom board
- Modification of Nintendo Famicom board
- Put the board in the case
- Modification completed
Tools required for work
Tools required for remodeling
- Phillips screwdriver
- Soldering iron
- Desoldering wire
- Thin nipper without blade spill
- Cellophane tape or polyimide tape
The desoldering wire looks like this.
Nippers, I found this easy to use. If there is a gap at the tip when the nipper blade is closed, it may not be possible to cut completely due to the spilling of the blade, which may make work difficult. If you can not cut well, it is recommended to buy a new one.
Removal of Nitendo Famicom board
Open the back cover
Turn the Famicom body over and remove the six screws to remove the back cover.
Removing the connector
Remove the connector from the controller.
Removing the board
Remove the screws of 4 places of RF board and 4 places of Famicom main board.
Removing switch wiring
Remove the cable connecting the red and white switches to the RF board, which is soldered.
Use a desoldering wire to remove the solder.
RF board separation
Separates the Nintendo Famicom mainboard and RF board. Cut with the cable on the mainboard side.
Cut with nippers.
Remove the wires remaining after cutting with a soldering iron. (If it is difficult, you can leave it as is)
Modification of Nintendo Famicom board
Adding a capacitor
Noise generated by memory access is mixed in the Nintendo Famicom video. In the case of the old RF connection (the method of connecting to the antenna line), this noise was not so noticeable due to the deterioration of the image due to RF. However, if the video circuit is modified this time, the image will be beautiful, and the noise that was not noticeable until now will be noticeable.
Therefore, measures are taken to minimize noise from memory access. There are two countermeasures.
- Add capacitors to reduce power supply voltage fluctuations
- Extract signal directly from video output pin
First, add a capacitor for noise suppression .
Attach the first capacitor to this location in the picture.
Cut off the extra feet with nippers.
Connect the ends of the arrows in the photo with capacitors. Deform the shape of the capacitor so that the foot of the capacitor does not touch the silver solder around it, and then attach it. If it seems difficult, you don’t need to install this second capacitor.
Attach the capacitor like this.
Cutting IC pins
This is the second measure against noise. When video and audio signals pass through the Nintendo Famicom mainboard, noise due to memory access generated by wiring passing close to the wiring will be mixed in. In the case of video images, vertical and diagonal stripe noises are introduced, and a buzzing sound is mixed in the audio signal.
In order to obtain a clear picture and clean audio signal, we will modify the signal directly from each output pin of the IC so that these noises are not mixed as much as possible.
Cut the board side of the IC pin and separate it from the board. Note that the board side of the IC is disconnected, not the package side.
Also, be careful not to forcibly bend the detached foot because if it is bent upward from the horizontal, it will come off due to metal fatigue.
Disconnect the upper left corner pin of the IC called RP2C02 from the board.
With the flat surface of the nipper blade facing down, insert the cutting edge between the IC pins and cut. If the blade is spilled, it will not cut well, but twisting or forcibly moving it will damage the board and IC pins. Let’s cut carefully without moving as much as possible.
Once cut, lift the pin horizontally. Do not lift any more upwards.
Disconnect the two pins in the lower left corner of the RP2A03 IC from the board.
Carefully cut the board side one pin at a time.
Once both pins are separated from the board, lift them horizontally. Please do not point upwards more than horizontal.
Preparation of shielded wire
For video signal
Two shielded wires, a thin wire and a thick wire, are included. Use the thinner type (1 core type) for the video signal.
Strip off 10mm of the black coating at the end of the shielded wire. Turn the white coating inside 5mm. Twist each wire, then infiltrate the solder and plate with solder.
Process the other. Here, since the wire of the shield part is unnecessary, cut from the root. Cut the white line to about 3mm after solder plating.
For audio signals
Process the thicker shield wire (2-core type). That’s the same point.
Peel off one black coating 10mm. Strip the white and black wire covering 5mm. Twist and solder-plate each wire.
On the other side, peel off the black coating 10mm, and peel off the white and black line coating 5mm inside. Twist and solder-plate each wire. Since the outer shield wire is unnecessary, cut from the root.
Cut the white and black lines as short as 3 mm.
This completes the cable processing.
Wiring to video board
Connect the video board and the pins of the Famicom IC with the shield wire that was processed earlier.
Use the thinner cable for the video signal. Solder the white wire and shield wire of this cable to the video board. Insert the white wire into “VIDEO” and the seed wire into GND and solder.
Only one pin of the Famicom main board has been separated. Solder the other white wire to the pin of the IC.
Secure the cable to the IC with cellophane tape so that it does not move. This is to prevent the pins from bending or being removed when the cable is put back into the case. Polyimide tape is used so that you can see how to apply cellophane tape in the photo.
Use the thicker cable for audio signals. Insert the white wire into “A # 1”, the seed wire into GND, and the black wire into “A # 2” and solder.
Solder the other wire to the two pins of the IC on the NintendoFamicom board. The pin at the end is white, and the black wire is soldered to the second pin.
Secure the cable on the IC with cellophane tape as shown in the photo below to prevent the cable from moving.
Attach the red and white cables to which the power switch of the main unit is connected to the video board. The left side of the hole is red and the right side is white.
The video board looks like this.
Put the board in the case
Return parts to the case
At First, Return the Famicom main board to the case.
Next, put the video board.
Insert the Famicom controller cable.
Tighten the eight screws to secure each board.
Wiring Famicom board and video board
Connect the Famicom main board and the video board with jumper wires (resistance leads).
As shown in the picture, connect “AUDIO”, “+ 5V”, and “GND” to the Famicom board.
Make sure that you make the same connections as shown in the picture so that you don’t accidentally connect to the next pin.
Connect the controller connector to the Famicom connector.
Put in cables
Route and store the cable as shown in the picture.
The shield wire coming out of the video board bypasses the screw holes at the upper left and upper right of the case and passes over the main board. If you do not bypass the screw holes, you will catch on the cable when removing the cassette.
Also, if you pass over the blue cartridge connector, the lid will not be closed. It is good to fix it with tape on the main board.
Screw back case
Close the back cover and tighten the screws.
Connect the video cable and confirm that it is reflected on the TV. In the above picture, the video is projected on a computer with a capture cable.