This modification adds switchless NESRGB and IGR (in-game routines / in-game reset) to a Nintendo AV Famicom.
A first look at the opened AV Famicom and the NESRGB kit. There is still a lot to be assembled. The installation guide for the AV Famicom can be found here.
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_01-1024x714.jpg)
The desoldered PPU – this is a difficult part as some of the pins are soldered on both sides. Even with a soldering gun it takes quite a while. Also note capacitor C5 that will be in the way of the NESRGB – better replace it with a new one that has longer legs.
![AV Famicom PPU](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_02-1024x789.jpg)
The fully assembled NESRGB kit, ready to be plugged into the new socket.
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_03.jpg)
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_04-1024x706.jpg)
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_05-755x1024.jpg)
The capacitor C5 is now lying under the NESRGB.
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_06-1024x533.jpg)
Add wires to the palette switch and to the MultiAV port.
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_07-842x1024.jpg)
The first step of the modification is done: The palette can be selected with an external switch.
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_08-1024x743.jpg)
![NESRGB for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_09.jpg)
NES IGR for NESRGB
For the switchless part we’ll need a daughter board: The NESRGB-IGR (or NES IGR for NESRGB) by borti4938. The repository was removed in the meantime, but parts of it can still be accessed via Wayback Machine.
![NESRGB-IGR PCB](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_01-1024x614.jpg)
The firmware for the PIC can be found in a copy of the repository that is luckily still online. I went for the nesrgb_igr_684_var_led.hex variant because I wasn’t sure if I wanted to use a LED with common anode or common cathode.
![Programming the PIC](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_02-1024x942.jpg)
The daughter board can be attached directly to the NESRGB using a pin header.
![NESRGB-IGR for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_03-1024x926.jpg)
A few more wires to intercept the reset and controller signals.
![NESRGB-IGR for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_04-1024x927.jpg)
![NESRGB-IGR for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_05-1024x846.jpg)
Final test:
![NESRGB-IGR for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_06-920x1024.jpg)
You can place the LED next to the power switch. When the casing is closed, you will see a dim glow through the switch.
![NESRGB-IGR for AV Famicom](https://retrostuff.org/wp-content/uploads/2016/12/nesrgb_igr_07-905x1024.jpg)
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