Welcome.... the control you are looking for is R118, Master Vertical Size.
This is a set up control , not to be confused with the Size control on the remote and does not have any direct relationship to aspect control.
This control is located on the first board (Vert Deflec) third one down.
This is a set up control , not to be confused with the Size control on the remote and does not have any direct relationship to aspect control.
This control is located on the first board (Vert Deflec) third one down.