My second attempt was just as bad as the first, with only one usable shot. I’ve ruled out any errors in my developing process by running another roll from a different camera at the same time. It came out fine.
A bit of research tells me that these cameras were prone to this failure. The wonderful click which I love is created by a mechanical symphony in motion. When the shutter button is depressed the mirror flips up, the aperture closes, and the shutter fires. If this sequence does not execute perfectly. . .
In my case, the aperture is slow in closing. Unfortunately, it is not reliably slow either. It is shooting at somewhere between f2.8 and wherever the dials are set. Perhaps a good cleaning would help, but for now it will go on the shelf as a display piece.
(My thanks to Mike B on G+ who alerted me to the possible problem and its diagnosis.)