July 2, 2013 at 11:39 pm #21369
It’s working now.
The IC seemed to be properly seated in the socket, so I pulled it and tested all the pins with a continuity tester, but there were no unintentional connections. I did observe two small blobs of solder underneath pins 12 and 13 on the socket side of the board, but they weren’t bridged. When I reinstalled the IC and rechecked it, the displays worked properly. I just needed to use a bigger hammer :-)
Thanks for the pointers.