Theory of Operation
3–56 1780R-Series Service Manual
provide a 2-field sweep. Remote sync is AC-coupled with an input impedance of
approximately 1 MW. Q392 is a switching transistor that is turned off when
Remote Sync Enable is present and saturates when there is no enable present.
Remote sync polarity is selected by changing a plug-jumper on Diagram 9.
RGB Amplifier. The RGB staircase signal from the rear-panel REMOTE connector
drives an operational amplifier composed of Q197 and Q195. The amplifier is
compensated for optimum step definition by C195 (RGB Comp). A DC level
can be adjusted out by R194, the RGB Offset adjustment.