The TACHYSCOPE LASER is made up of a 12" rotating platter ( turntable) , A fixed He-Ne 9" long laser tube. Circa 1980, A mirror mounted to a mini stepper motor acting as the galvanometer and a 1/2" by 6" semi-transparent target (stick).
Line Level audio is fed into the power amp consisting of (4) UV-201 vacuum tubes . 100 + years old , The output tubes V3 and V4 drive the galvanometer via a multi pole slip ring.
The laser is always lit up ( powered On), no modulation.
RPM speed is PWM controlled to 100 RPM or so, faster speed = closer the image on the POV.
Laser light for the static laser tube is sent via mirrors up the centre of the hollow drive shaft, upon exiting, the light is redirected horizontally via the Galvo / mirror assembly and "hits" the target display attached to the perimeter of the platter.
Not described here for this project
Decatron counter tube
(2) Nixies display tubes
10 white Leds secondary POV display an