Engineers are fond of their calculating gear. Nostalgia, so they tell us, derives from the Greek word for pain. There is certainly a bond formed in pain across many late nights, many problem sets, and many many wrong answers.
The generation before mine cherished their favorite slide rule. I know many of my contemporaries who swear by their trusty Reverse Polish Notation HP calculators. But this was the machine that saw me through college and graduate school. This one was mine.
Behold, the Sharp EL-5100S Scientific Calculator. Isn’t she a beauty?
I bought it at 42nd Street Photo in New York when I was a freshman in college. I enjoyed the adventure of going to a special store to buy a special machine. And I never saw another one like it. You had to know exactly what you wanted when you walked into 42nd Street Photo, because the store staff would yell at you and dismiss you if you were uncertain. “What do you want?!” I forget where I got the recommendation, but I knew what to ask for and they had it.
What made it great? It had a super wide pixelated display. This meant you could not only enter (and see) long expressions, but also that all the text was more legible more capable than a typical seven-segment digital display. Press the Pi button, and you saw the dapper Greek letter itself, not some bastard numeric approximation. It had backspace and delete keys, so it felt more like computing with a small screen than calculating with a big screen. I could type in lavish, extravagant expressions and survey their stately architecture before pressing the equals key. Then, if the result smelled sour, I could press the PB button (for “playback”) and review my input for mistakes. Backspace backspace fix fix fix, and off I went. Luxury! That playback button saved me so much time.
It’s been twenty five years since I used my 5100S in anger. Atop a bookshelf in my study, it’s had time to ponder its fate. Periodically I’d pull it out and consider either throwing it away or rehabilitating it. I couldn’t bear to do the former, and I couldn’t be bothered to do the latter. But this virus-enforced home stay has had me snooping and tidying in every room in the house. It was time to make a decision: I decided to see if the old girl could still dance. I bought some Duracell 76As and plugged them in.
No dice. Sadly, my little friend wasn’t going to come back to life. I wonder what happens deep in the circuitry of a solid state device to make it stop working? Is it sad? Is it angry? It’s probably something simple, like a bad resistor. But I’ll never know. It was an exercise of pure nostalgia.
But I can still slide it out of its case and see possibilities and power, pain and perseverance. The keys still spring under my touch. The calculator is the engineer’s wand, or it was before still more powerful machines displaced it. With it, you felt the ability to summon, to penetrate the unseen, to conjure great things into existence. Not that those things necessarily happened, but it felt that way at times. Other times, of course, it felt like an anchor, shackling you to the desk even as your English major friends went out for beers and laughter and late-night liaisons. It’s all there for me, those memories of thermodynamics and aircraft control theory and convergent-divergent rocket nozzles. Memories of things lost and gained. A bargain of time and sweat for… what? I never built an actual rocket. But I did come to understand the made world. I remain grateful for that. And I remain grateful for this little helper, my familiar, my companion.
Thanks, old friend!
Rambles Blog at Star Chamber 
Try some BW-100 Non-flammable Contact Cleaner on the PCB.
I will! Thanks for the tip.