July 6th, 2022—
In 1979, Sony launched the PS-X75 turntable. It quickly gained popularity thanks to its high-fidelity sound output and ease of use. It was easy to use because it was fully automated–a common feature today, but something that was quite exciting at the time. To perform that automation, the PS-X75 contained an integrated circuit that detected record size, dropped the needle, and so on. But that IC was prone to failure. To revive their Sony PS-X75 turntable, MKB-1 used an Arduino Mega to replace the original circuit.
Unlike earlier turntable designs, which were often entirely electromechanical, the PS-X75’s IC controls almost all of the turntable’s functions digitally. That means that when the IC fails, the turntable becomes inoperable. Replacement ICs are almost impossible to find and haven’t been manufactured in many years. For most people, this means that the PS-X75 becomes e-waste when that IC bites the dust. But MKB-1 has some reverse-engineering skill and was able to save their PS-X75 by swapping out original IC for an Arduino Mega.
MKB-1 was able to achieve this impressive feat by carefully studying the original PS-X75 service manual, which included detailed schematics and details on each function’s electrical operation. With this info, they replicated all 42 of the original IC’s connections on an Arduino Mega 2560 development board. They chose the Mega because it had enough I/O pins available to handle all of those connections. Their custom Sketch handles all of the original functionality, from reading button presses to lowering the tone arm. If you own a PS-X75, MKB-1’s detailed Instructables tutorial will walk you through how to perform this retrofit.