Beamfinder is working properly. When pressed, the display compresses to a single position on the x-axis, but the amplitude remains. Here is a helpful hint...I pulled (disconnected) the upper and lower plate deflector wires from the CRT and turned the unit on again... without any vertical input connected, the CRT display was exactly the same as before...just a big rectangle-appearing image at all sweep speeds. This tells me that something is amiss in the CRT or associated electronics. Still scratching my head on this one.
Phil