I see a tiny "aperture" (a block dot) inside the meter cell window and I also see another dot at the far right edge of the meter cell window. However neither of these move or change size as I adjust the aperture. I'm doing all this without a battery in the camera, but I'm assuming this is a mechnical function.
It looks like I'll be on the lookout for a camera repair place in Boston to handle this for me. Thank you for the explanation, Fred.