For most of us, a calculator might have been superseded by Excel or an app on a phone, yet there remains a die-hard contingent with a passion for the push-button marvels. So, the shocking discovery of an apparently rogue HP-12C has sent tremors through the calculator aficionado world.
The HP-12C [PDF] is a remarkably long-lived financial calculator from Hewlett-Packard (HP). It first appeared in 1981 and has continued in production ever since, with just the odd tweak here and there to its hardware.
Murray wrote a lengthy blog post on the topic and put together a battery of TVM tests designed to stretch the TVM solver and found to his, and others, surprise, that not all HP-12C units were equal. Dubbing the unit the “rogue edition,” Murray demonstrated some worrying bugs and differences in the “rogue” hardware, which was shipped from Brazil, versus another unit.
So his test may be useful to others to do a check on their HP to ensure it is 100% accurate. Maybe even a rogue version is found to be accurate, so it won’t be proof that a calculator is an original HP.
See https://www.theregister.com/2024/09/21/hp_12c_calculator_mystery