vintage machine examples
KEELER model 6303 polygraph machine
The Keeler Model #6303 was a hybrid between the Keller Model #302 and the Model #6308, the first of the PaceSetter Series of polygraphs manufacturered by Associated Reasearch. It was a sleeker design than the Model #302, but still used vacumn tubes. Associated research replaced the stainless steel face with a blue acrylic faceplate.
It had three seperate channels. Pnuemograph, cardiograph, and galvanometer.