I built the clock about a year ago and everything worked fine. now the display does not light in any of the four digits on the cross segment. otherwise all is good. My solder joints appear good. Any ideas what I can do to diagnose this problem.
Sorry to hear that. Yes, you can check the connections that are associated with the cross segment (segment “G”). Here is an image that shows which connections to check (as viewed from the top of the board). If you reheat the solder on each of these, it will probably start working again.