last week the door wouldn't open, only hummed. checked all the settings and the center limit contact was positioned as if the door were open but it was closed. I rest the chain and the set screws, worked for a few days, then limit contact was in the wrong position again, but I was able to use the setting screws to adjust, next day it wouldn't open all the way, again adjusted the setting screws. next day same thing. I'm guessing the logic board is bad but can't fine anything to confirm this