I don’t know why I picked it up. Maybe because there was just enough power left in the batteries to run a couple of calculations and the self-test before they died, but for $2 I bought a circa-1983 HP 12C financial calculator. It’s missing the owner’s manual, the vinyl sleeve is in tatters and the quick reference lost its spiral binding long ago but the calculator itself is in excellent shape.
$9 worth of button cell batteries later, I have a working RPN calculator. It’s a neat little device and HP still sells it in two models- one of which switches between RPN and Algebraic modes- and supplies (pdf) manuals and guides:
- HP 12C Summary
- HP 12C Solutions
- HP 12C Users Guide
- HP 12C Quick Start
- HP 12C training modules [4.2MB zip]
I don’t know what I’m going to do with it but I’ll leave on my work desk and see if I use it. I usually have a Lisp session open in a terminal or a newer, faster computing device nearby, but it’s quite fast for what it does compared to slapping together a one-off and checking the result.