The Casio J-3 is a basic 6 function calculator produced by Casio in Japan. The main features of this calculator are its memory functionality and large display.
Internal design[edit | edit source]
This calculator is based upon the Hitachi HD38401 calculator ASIC, which incorporates the key matrix polling, arithmetic, and display control all into a single chip. The Casio J-3 uses an unusually large vacuum fluorescent display module, the Toshiba E6610, with thirteen 9 segment digits.
The key mechanism used consists of sheets of conductive plastic that are pressed against a metal pad by the keys, normally held apart by a non-conductive sheet of plastic. As the calculator has aged, the actuation force required for a key press has increased significantly. The keypad PCB is connected to the main board by uninsulated copper pins, over time these can become damaged from repeatedly opening the calculator or can be corroded away by battery leakage.