All zones run when the controller is unplugged
The very first night this happened, I unplugged the controller. All zones continued to run. Since then I have also turned off the main valve, unplugged the controller and then turned on the main valve. All zones turn on again. As I said before, all zones run no matter what I do with the controller: unplugged, manual operation, auto operation, on position, off position .... all zones run.
Just today I found a second solenoid box in the front yard so now I have something else to work with. It's going to rain within the next 24 hours or so here so I will probably not get to work with it again until this coming weekend. Just curious, why would they put two solenoid boxes in the same side of the front yard? You would think they would be spread out. Unless, of course, one of those boxes is for the landscaping in front of the house (on the front wall). Both of these boxes are right on the surface so I am puzzled why I can't find the other boxes.
Thanks again for the suggestions. Everything helps. I just don't want to spend 5 or 6 hundred dollars on a repair service.