Originally Posted by
Kevint
OK, still can't sleep.
The circuit on the left. If 10 is shorted to ground it turns the transistor on, voltage is then passed to the JFET to amplify signal 4. 5 is a square wave input and H I'm guessing is a sawtooth/triangle ramp. Both of those signals go to the multiplier. Not sure of the pinout for A9 or what the output of A9 pin 4 looks like. A multiple of the square wave and H.
Going to sleep now. Maybe.
A square wave generated on the spiral card (later used for blanking) comes in on pin S. A 0-10V signal comes in on pin H that controls the amplitude of the square wave. Pin 10 just enables the signal to get to the X axis summing amp. It was just a somewhat adjustable square wave signal added to one axis of the fixed cycloids. With fixed rotation enabled with slow variable rotation it was a nice look in Laserium II's Summer Madness.
"There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso