If the garage door opener makes a grinding noise but the door ... Too little tension could cause the chain to skip off the sprocket and fall down on your car.

Too little tension could cause the chain to skip off the sprocket and fall down on your car. Garage Door Won't Open All the Way: Check the Chain Tension Most chain drive openers suggest you ...

The garage door was first outfitted with a pair of reed switches to sense when it was fully open or fully closed. The drive sprocket of the garage door was also set up to be monitored with magnets ...