Depending on the model clock you have, if you open the front panel there should be a fuse inside. Replace the fuse and if that does not work the transformer has probably shorted out. If it's an indoor clock with an external transformer it can be replaced if it's got a built-in transformer the clock may have to be replaced.

Thank you mike1059 for your input. We checked over the irrigation box again and read the Hunter company's online info which mentioned the transformer and the possibility of a lightning strike causing a problem. The landscaping company that installed the Hunter system found that the circuit board had been damaged probably due to the horrendous lightning strike. He unhinged and removed the compartment containing the setting controls/circuitry and came back an hour later with a replacement part. Thank you again for your help - it was appreciated.

How much was repair, I have same issue after hurricane Irma. System was unplugged before storm to prevent surge. Plugged back in after storm and blank screen. Have power at receptive. And with battery backup can continue to program bit not operate.