Famicon cart of Hudson Soft DYNABLASTER??

[P]

Famicom/NES has no RGB output, only composite (AV) so that RGB cable will probably not work on any Famicom (or maybe it autodetects composite, I don't know). Lot's of info abour RGB and what RGB cable to use with what system here: http://retrorgb.com/. A composite cable usually comes with the system so don't worry about that yet.

PAL Megadrive Model-1 should technically work on a US SNES but I heard the plug size is different so I'm not sure. It won't work on a Twin either for reasons I stated before. It should work on an AV Famicom though. Study the guide I posted before and ask about things you don't understand.

I don't recommend getting a step-down just for a Famicom system. They are expensive and the original adapters may already have gone bad anyway in which case you need to get a new one either way.