Does anyone have the manual of Craftsman 139.53681B garage opener that you may send me? The opener does not work and I do not have the manual to reprogram it.
The model number you gave is for the remote. You may have better luck with the model number off the motor unit.
You can find the remote control manual at http://www.hammerwall.com/Manuals/Craftsman/Description/139.53681B/Craftsman%20Security%20Plus%20Remote%20Control/L0804154/
Or you can look at the craftsman garage door manuals at
Here is a link that might be useful: Craftsman Garage Door Manuals