Hello this is my first post. Sorry if I am not in the right place. I am trying to fix my garage door opener. I did a replacement of the main sprocket gear and now when I push the button it only opens a out a foot then it immediately closes. What can I do pleas help
Check the RPM sensor, the black segmented wheel on the end of the worm drive shaft. Make sure it is pushed all the way on the shaft so that the segmented rim actually splits the pickups of the sensor board. Also make sure the wires are plugged into the sensor board correctly, not disconnected or off by one pin.