The Vertical Interface in a 7704A (Schematic 5) has two potentiometers, R2234 and R2284, connected to the LEFT & RIGHT VERTICAL PLUGIN_SELECTOR IC (U2230 - a 0022 chip) for which I can't find any references in the calibration chapter of the service manual. Have I simply overlooked it? If not, does anyone know if those should be part of a calibration and, if so, how to do that?
Thanks,
Barry - N4BUQ
