Lately, our garage door opener has been acting up. We have a rolling
metal door, and it goes up just fine. But when we try and lower the
door, the opener unit flashes as if there's an obstruction and the
door reverses direction and goes back up. We can find no obstruction.
If we push and hold the wall-mounted button, it will lower the door
all the way, but only if we hold the button for the duration of the
lowering. Any suggestions on how to fix this problem?