I shut off the power to this entire house, from inside, the larger main switch at the top of the panel. 12 hours later we started hearing the garage door opener circuit board make a noise like a relay flickering. Seems it's toast upon inspection (ordered part for $60).
Would a small surge protector like the one below prevent that from happening again to another $200, 10 year old device like that?
Backstory: We bought this home and have found some weird stuff I've yet to dig into. 50-90vac on some of the switch plate screws. Other places, 30vac still when the circuit breaker is off. Other outlets have only 30vac hot to neutral. All on one line luckily. But that's another question for another time. I will check all that out later this month.