Vintage British Calculators

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President Scientific

Sinclair President

Display is 8 digits, blue vacuum fluorescent.

Scientific functions.

3v (2x AA battery).

Integrated circuit: General Instrument CF-599.

160 x 94 x 28 mm (6.3 x 3.7 x 1.1 ins).

Late 1970s.

Assembled in Hong Kong

The silver paint on the President models is notorious for wearing off at the corners, as in the example photographed above.

The President series were some of the last Sinclair models and are rather large. This is ironic considering that Sinclair was famous for its first model, the Executive, which was very small.
These are is also the only Sinclair calculator models not made in England. By now the calculator market was very competitive and Sinclair made use of the cheaper manufacturing costs in Hong Kong. The circuit boards are marked Radofin, a British based company which also had a subsidiary in Hong Kong.


With the back removed. Note the "Radofin" name on the keyboard circuit board.

Radofin was a company based in both London and Hong Kong which also sold calculators under its own name.


The main circuit board of calculator. Prominent are the vacuum fluorescent display (VFD) and the General Instrument calculator chip.
This board is also marked "Radofin" on the back.

Vintage British Calculators

Text & photographs copyright, except where stated otherwise, © Nigel Tout 2000-2024.