Inside Sinclair Spectrum Joystick Interface Add-on

The spectrum joystick interface has a pair of SN74LS366 integrated circuits (IC), which are hex inverting buffer drivers with tri-state outputs. It is an extremely common and low-cost IC with many equivalents.

PCB View

The circuit simply buffers the I/O lines of the Sinclair Spectrum.

Circuit Board

If you are planning to build your own joystick adapter, then here is the PCB track layout, which you can trace to determine the circuit. However, there are many circuits available on the Internet and books.

PCB View

It is a nicely etched printed circuit board. This extremely low-cost and simple product was very popular at the time.

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