I found an ancient calculator (a Commodore "Minuteman
6" -- yes, that Commodore) that I used when I was in elementary school. It belonged to my dad. The calculator was first sold in 1974.
The power leads from the battery snapped off from the main board decades ago, but now I have a Hakko desoldering tool, so I was able to clear out the through-hole solder points and reattach the wires from the battery. It has a 7-segment red LED display and minimal operations.
And...it works! Sort of. I seem to have gotten it into a sort of self-test mode that displays a scrolling 0, until I power cycle it, then it displays EEFEEE until I hit the Clear button. And some of the segments don't illuminate. But it hasn't felt electrons surging through it since the 20th century, so I'll cut it some slack.
Welcome to the future, time traveler!
https://calculator-museum.nl/calculators/commodore-minuteman6-body.html