Need a manual for sears model 139.18856, 1/2

I have a Craftsman garage door opener model # 139.18856. I have looked all over the internet and there are a few people calming to have the same motor and people are telling them that they don't exist. I have attached a photo of this motor with model number to show that yes craftsman did make this at one time. Having said that, Im having a similar problem as this guy. When I press the button to close the door, the light blinks 10 times and stays on on the tenth blink. The output sensor stays green and the receiving sensor only flashes green when you put something in front of it, then move it away. I have cleaned both sensors, nothing is blocking it and the wire's look ok. If it is a sensor problem, can i use any sensors or do I need the sensors that came with this model that never existed. Thanks, Sam

I have a Craftsman garage door opener model # 139.18856. I have looked all over the internet and there are a few people calming to have the same motor and people are telling them that they don't exist. I have attached a photo of this motor with model number to show that yes craftsman did make this at one time. Having said that, Im having a similar problem as this guy. When I press the button to close the door, the light blinks 10 times and stays on on the tenth blink. The output sensor stays green and the receiving sensor only flashes green when you put something in front of it, then move it away. I have cleaned both sensors, nothing is blocking it and the wire's look ok. If it is a sensor problem, can i use any sensors or do I need the sensors that came with this model that never existed. Thanks, Sam