Novus 4520 batteries and charger question

From: Tom R.
Email: worldlysaint@gmail.com


I have a Novus 4520 calculator, circa 1975. The three rechargeable batteries have leaked. I am looking for information about (a) the voltage of the batteries, and (b) the voltage and amperage required for an AC adaptor for this model. I have the original manual but it provides no answers to these questions. Any help will be appreciated.