When I push the button the door opens about six inches and then closes. This will happen if the trolley is connected and when it is not connected to the door. When the trolley stops the light do not blink. I have ruled out the door since it does it with out the trolley connected. I have tried the following things:
Looked at the gears and the do not looked stripped.
Lubed the rail
Tightened the chain drive.
Looked at and blew out where the chain drive connects to sprocket at top of opener
What else can I look at?