That said, I've never had one slot completely die on me either (I've had some more finicky than others, but I've always been able to get it to work sooner or later.
I have had ones completely die on me.
Are you sure you didn't just give up early? I've had to try like hell a few times with mine, booting Vampire Savour like 20 times in a row to learn its not seeing right, before it finally takes and then runs perfectly as long as you don't touch it.
I spent hours trying to get cartridges to load on some of these Saturns before breaking down, making the trip to Funcoland back in the day and buying another one. Eventually Funcoland had a system where if you bought a cleaning kit and some other crap, you got a 1 year warranty. At the time I actively used the Netlink, had a PAR I used for imports, had an official Sega memory card, an interact brand memory card. And also a game shark, ST key, and an EMS brand white backup memory card. I wore those cartridge slots out in a few months and kept swapping them. Eventually Funcoland quit buying back Saturns and I couldn't keep swapping them for ones with newer cart ports. Since then, I've still gone through a few Saturns.
So yes, I've completely worn them out to where they won't read anything, backup memory cards, RAM carts, netlink, etc. With that said, most of them will read backup memory cards if I try enough times and don't move the system.
