I have a 1/2 HP Sears Craftsman Garage Door Opener. Lately, when I open the door first thing in the morning, the door opens completely, then the LEDs go out on the two blockage sensors mounted at the base of the garage tracks. When I try to close the door, it goes down about 6 inches, goes back up and the light flashes ten times. This is because there is no "clear" signal being sent from the sensors. Electrically, everything else looks good (lamp on head comes on). After about ten or 15 minutes the lights re-energize on the sensors, and I can close the door. The unit is only two weeks old.