I hate those EA carts. I hate them so much I built one in Minecraft then blew it up with a nuke mod. All while being a pony... I had a real one for MADDEN NFL '94 that I sold to a member here. I even modded it with 2 batteries for extra long save life. I was glad to get it into the outgoing package PRONTO!!
I've found a pin layout to connect a Mega Drive cartridge slot to the Radica console. Looks pretty easy apart from tinny solder points.
That should read connect a limited cartridge slot. It won't work for games with SRAM or bankswitching. Perhaps the other signals can be tapped elsewhere, but probably not.
Ah, there's a mod to fix that which they call the SNK mod. You can read about it at http://devster.monkeeh.com/sega/radica/ I don't think I'll bother with that though. Too much for me plus this is going to be just for fun, not a daily console..
"SNK" = Sonic & Knuckles. I would do it, it will let you play most games, though you still won't be able to save without finding points for the write strobes. The mod means breaking the internal game support, since the signal is being used for their bankswitching too.
There are no points inside a Radica to allow for SRAM saving. The signal would have to be externally generated. "Breaking the internal game support"? If you mean what this sounds like then that won't be an issue since the mask ROM the original games are on is removed. If you want to have the 6 games playable, there is a how to for putting the ROM in a cart with switches to manually select game banks since the bank switching system the ROM used stays behind on the Genny and is in fact partially used for the now famous SNK mod.