Thanks for the suggestion. The libraries looked right (except that the Time library is called Time-master), but I uninstalled the Arduino IDE and reinstalled it. I loaded the clock code and the three libraries from GITHUB, as specified in the entry for the Angular Clock entry. I still get this compilation error:
AngularClock:60: error: 'tmElements_t' does not name a type
tmElements_t tm;
^
I'm frustrated. What am I doing wrong here? One way or the other (even with a new cable, which I don't think is the problem), I'm going to need to reload the clock code, so I'm stuck.
Dick