Thanks for your reply.
I have the manual, a PDF of the original, which states that the standard signal output is a square wave, 0.5V p-p at 1 kHz. The procedure which I am following is as follows: Trig Slope = Pos, Trig Mode = Normal, Trig Source = Internal, Vertical Axis Coupling set to AC, Trigger Level set to Auto, Horizontal and Vertical Trimmers (inner knobs) set to Calibrated, Horizontal Time/CM set to 0.2 mS, Vertical Volts/CM set to 0.02, image adjusted to center of the display.
At this setting I see 3 wave tops and 2 wave bottoms, clearly defined, about 1 division (CM) apart vertically, each wave. The horizontal lines are nice and flat; the top traces are about 2.2 CM long, the bottom ones about 2.6 CM long. There is a very faint vertical trace visible, but not nearly so strong as the horizontal image.
Every reference I have shows a symmetrically shaped and equally strong vertical and horizontal line. That's what has been confusing me. Is this normal, or should the image look like a "square wave"?