Garage Door Is Lifted Off Ground
Your garage door s logic board is the brain of your garage door opener.
Garage door is lifted off ground. If the lift of the springs is greater than the weight of the door the springs will lift the door off of the ground. To help lift a heavy garage door the springs apply twisting force to the torsion tube. When the logic board wears out it can cause your garage door to close then open and vice versa without explanation. The most common problems with this system are broken springs or cables.
If that point is more than four feet or less than three feet above the ground you will need to balance the door. Since most photo eye sensors are placed at that two inch height most people know you can simply step high above the infrared light to bypass the system. If one of the photo eye sensors are malfunctioning it will begin to blink rapidly. When the door is in the closed position the release cord should be located near the front of the door.
Smaller doors often have just one spring. When the sum of the forces applied to the garage door due to the tension in the cables is close to the force on the door due to gravity a much smaller applied force human or opener is necessary to open the garage door. This brain can wear out in time so you could need a replacement. The trolley is connected to the door and moves as it opens and closes.
Drums at the ends of the tube act as reels winding up the cables connected to the door. The photo eye sensor for a garage door opener is typically placed approximately two inches off of the ground.