Hewlett-Packard HP 28C (Clamshell? PALADIN)
The Hewlett-Packard HP 28C is a graphing calculator with 10 digits precision and RPN (reverse polish notation) logic. It has 1500 functions, 78 keys, and an LCD (liquid crystal) display.
Facts at a glance:
Note that diagnostic tests generally delete any data on the calculator. Be sure to back up any important information held in the calculator before running these tests.
Hold down ON button and press fourth key on top row of right-hand keypad, then choose test from menu (use EXIT to leave test and go back to menu). Use ON and fifth key on top row to run a test sequence. Use ON key and third key on top row to reset calculator after tests.
If you have a Hewlett-Packard HP 28C that is no longer working, you can consider replacing the calculator with a modern equivalent. We suggest the following current model as a replacement: