Bought a new Rachio 3 and when I plugged it in nothing happened.
First quadrant white light blinked twice and then nothing.
Tried to restart numerous times - unplug, press bottom space button for 5-10 seconds to drain power and then plug in again - nothing.
Tried to factory reset numerous times - press and hold top button - nothing.
As a last resort I tried the old Fonzi from Happy Days trick!
Sharp tap to the side of the unit.
Booted up perfectly and now works fine!
Worth a try if all else fails!!!