Don’t be afraid of your sprinkler control box. It’s nothing more than an elaborate wall clock or wristwatch.
Most sprinkler boxes, if unplugged, have internal factory reset – just in case you make a boo boo. Most time box problems are nothing more than spider webs and dust clogging up the system.
Unplug and unscrew the face of the box. Gently pull open – There will be wires attached so don’t pull too far, now, with a vacuum slurp up debris or blow out with a compressor. Put it back together, plug it in reset and you’re off.