Theory of Operation
1780R-Series Service Manual 3–59
edge of the /Sample RO from the Readout State Machine. U560B drives the
Vertical Output Amplifiers of the CRTs; R555 (V Shape) is a gain control.
U560C and D, which are also driven by the sample-and-hold output, provide an
increase in drive to the Z-Axis Amplifier when readout segments or cursors are
being displayed.
Horizontal Sample-and-Hold operates in the same manner, except that the gain is
2 (instead of unity) in the comparator circuit.