Preisvergleich für Hp 15c Scientific Calculator in Deutschland bei Shoppdeal.de in October 16, 2019
3 scientific calculators for electronics buffs. Support Roger on Patreon: https://www.patreon.com/kainkalabs Each one with unique features not found anywhere else: HP-15C: http://www.hpmuseum.org/hp15.htm HP "Voyager" Series with HP10C, HP11C etc.: https://en.wikipedia.org/wiki/Hewlett-Packard...
Introduction to basic programming on the 15C. Please leave a comment if you have additional information to share or if there are some things I got incorrect.
I hope this helps the owners/users of the vintage HP calculators save their instruments from the trash bin by a simple reset procedure. I cannot guarantee this will fix your calculator but it is an easy attempt to clear an otherwise incurable error condition.