These machines had an optical groove location system. The small screen on the left behind the turntable displayed a scale indicating the position of the arm.
The turntable plate rested on felt pads and the start/stop lever caused the rotating turntable to rise or fall beneath it. This used a mechanical link and gear system and the lever had to be operated gently to avoid making the stylus jump out of the groove. As the turntable rose the motor volts were boosted to increase the starting torque. Initially the machines were fitted with a muting control to prevent wowed starts, these were later disabled. Set-up was easy, of course, as the disc could be wound back without causing damage.