Keyboard Matrix

The reverse side of the keyboard reveals the PCB traces and the keyboard matrix. It appears to be a very straightforward design found in most calculators of that era. It is amazing to think that this bright orange coloured PCB with shiny soldering still works today. You can see that the manufacturing was to a very high standard.

Metal Keyboard chassis

The PCB mounts on a metal chassis, which also secures the switches on the reverse side. It was a very robust keyboard, which lasted all this time.

Keyboard Matrix Circuit

Here is a small circuit diagram of the keyboard matrix. Port lines d1 to d11 connect directly by the calculator chip, which scans them for input. It is a very simple and straightforward design.

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