Do you remember what model/brand the one for your Amiga was?
But that's awesome that your Casio still works.
I often wonder about modern electronics, and how they will hold up over decades.
My Bose Companion 2 speakers/subwoofer are probably about 18 or 19 years old, and still work. That generates a lot of heat because it has a built-in amp. I forget when they banned lead solder, but it definitely lasted way longer.