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Inside the Sinclair Scientific

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This Sinclair Scientific was sold as non-functional. The metal plate of the power switch was missing.
I supplied this calculator with 6 Volt, but it didn't generate the expected internal voltages. Measurements
showed that two out of three windings of the small power transformer are interrupted.
Unfortunately these transformers are not standard components.

Sinclair

The plastic housing parts of this calculator.

 

HP9G case frontHP9G case back

The photo's show both sides of the PCB. Build as expected. On the front site the keyboard and the display, and on the back site the electronics.

The calculator is build with a chip set of Texas Instruments. The heart of this calculator is the RPN single chip calculator chip: TMC0805. This calculator also uses the IFC1 LED digit driver and the IFC2 power converter chip.

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Sinclair Scientific inside related links:

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