[round_midnight]

Kind of a puzzling end to this story. I ordered a new alternator from Summit. I got ready to install it and decided to do a couple of the things suggested. I wiggled the battery cables and found them to be tight. I hooked up a voltmeter to the alternator output and started the car. Voltage was rock solid at 14.5 V! Have started it several times since, and no further problems. So, I guess I just need to keep an eye on it to see if the problem returns, and see if Summit will take the new alternator back. Thanks to all posters for your help and advice.