The Calfax 820-CD is an arithmetic calculator with algebraic logic. It has an LED (light-emitting diode) display, typical of calculators of this era. The power source is PP3 9V.
Facts at a glance:
|Power Source||PP3 9V|
If you have a Calfax 820-CD that is no longer working, you can first try replacing the PP3 9V battery. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent.
We suggest the following current models as possible replacements: