On a recent trip to Florida I purchased a working HP-45 with an 82002 charger for three dollars. That made a real improvement in my collection since my only other HP-45 had missing segments in the display and an intermittent charger connector.
I also purchased Casio S-1 for a dollar. It's not listed in the Flamm book. It seems to work well but I have been unable to figure out what the switch with the following six positions does:
6 4 3 2 1 0 ADD(2)
Can anyone help?