I pulled out my old HP-67. I had written a bunch of handy programs for chemistry, and wanted to use them for a class I’m teaching. Using a new battery pack, It worked OK, but the card reader was dead – made noise but the cards didn’t move. Doing some research on the DVDs I bought from the Museum of HP Calculators, I repaired the card reader. Thanks to the helpful individuals who took the time to write up their work on this repair.

I enjoyed relearning about this wonderful machine! It’s powerful but slow. Sure to draw comments in a roomful of geeks like me! A friend sold me some parts from his HP-67, including the charger. Since this charger charges the batteries with a constant 60 mA, I decided to modify it to work with NiMH batteries (lowering the charging current). This modification is detailed on the Batteries – Chargers page.