The garage doors at my dad's house are operating inconsistently. The problem is impacting both doors. When I checked out the problem initially, the motor would whir a bit and then stop on the door I was trying to open. I figured I had two old garage door openers and thus replaced both of them. I just got word that the problem has returned. Any ideas? I'm wondering if I have an electrical problem, that the doors are not getting enough juice. What's wears is that one door will work fine and the other won't open or close. Thoughts?