NESRGB-IGR for AV Famicom

Switchless NESRGB for AV Famicom

This modification adds switchless NESRGB and IGR (in-game routines/in-game reset) to a Nintendo AV Famicom.

First look at the opened AV Famicom and the NESRGB kit. A lot of assembling needs to be done.

NESRGB for AV Famicom
NESRGB for AV Famicom

The desoldered PPU – this is a hard part as some of the pins are soldered on both sides. Even with a solder gun it takes quite some time. Also note the C5 capacitor, which will be in the way of the NESRGB – better replace it with a new one that has longer legs.

AV Famicom PPU
AV Famicom PPU

The fully assembled NESRGB kit, ready to be plugged into the new socket.

NESRGB for AV Famicom
NESRGB for AV Famicom

The C5 capacitor is lying right underneath the NESRGB.

NESRGB for AV Famicom

Add wires to the palette selection switch and to the AV port.

NESRGB for AV Famicom
NESRGB for AV Famicom

The first step of the modification is done: The palette will be selected with an external switch.

For the switchless part we’ll need a daughter board: The NESRGB-IGR by borti4938.

NESRGB-IGR PCB
NESRGB-IGR PCB

There are a couple of hex files for the PIC. The code explains the differences and I went for the var_led variant.

Programming the PIC
Programming the PIC

The daughter board can sit right on top of the NESRGB with the help of a pin header.

NESRGB-IGR for AV Famicom
NESRGB-IGR for AV Famicom

Some more wires to intercept the reset and controller signals.

NESRGB-IGR for AV Famicom
NESRGB-IGR for AV Famicom
NESRGB-IGR for AV Famicom
NESRGB-IGR for AV Famicom

Final test:

NESRGB-IGR for AV Famicom
NESRGB-IGR for AV Famicom

You can place the LED next to the power switch. When the case is closed, you will see a dim glow through the switch.

NESRGB-IGR for AV Famicom
NESRGB-IGR for AV Famicom

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