My Classic Collection of HP Calculators is Growing

Here's a quick picture of my HP calculator Classic series collection. OK, the HP-67 (bottom left) is technically not from the Classic series (it was based on the same technology used in the later 20 series). Ages range from 1972 for my HP-35 (top left) which has the famous 2.02 bug, to the HP-67 made in 1979. A couple of duplications (two HP-80s and two HP-65s).

All working but I had to rebuild the card readers in the HP-65s and the 67. Note the HP-35 and one of the HP-80s are the early models without the model number on the bottom label and with the stainless steel metal strip above the ON/OFF key. Probably the only design feature HP must regret changing in later versions, presumably to save costs.

So apart from the numeric and arithmetic keys, what is the only key with the same characters and in the same keyboard location on all the calculators except the HP-35? No, not ENTER or ON/OFF either. Some Thing Other.

Which was the cheapest and most expensive at launch? The HP-70 is the one Classic series calculator I'm still missing. It launched in 1974 at $275. The HP-65 launched in the same year at an eye-watering $795. The rest all launched at $395, still a tidy sum in the mid-70s. (OK, I know you're asking. The HP-67 sold $450 in 1976 reflecting the production savings from the newer technology it used.)

As an interesting side-note, Classic series calculators in good condition can sell today at or even above their original purchase price. Not bad for a piece of forty-year-old technology!

My favorite? No doubt the HP-65. It was the most technically complex of the Classic series and set the reference design for many future HP designs including the HP-67 and HP-41. Notice the  top key row labeled 'A' to 'E'? These were user-definable label keys that we'd call programmable soft keys today and they featured on many HP calculators after the HP-65. Even the tiny magnetic card used by the HP-65 was the 1970s equivalent to today's USB flash drive, although it could only store program instructions. (Look out for a future blog entry on the HP-65.)

In today's era of throw-away consumer electronics, HP's Classic series of calculators reminds us that there was a time when products were built to last, not just a few years but even several decades. I wonder if people will be collecting iPhones in 2056?

All the best and cheers for now!