Thanks Don, I should've mentioned the up force was at 9. I found and called the cust svc number 800-528-5236, and they made me lower the up force to 5, manually lift the door waist high and drop it. Since it slammed to the ground, their conclusion is that the door is not balanced and thus the GDO is doing all the work. they recommended a couple of repair guys to do what's called a Door Balancing. Does this make sense to you? Thanks again.

If tapping on the unit restores function the first thing I would look for is a loose connection. BTW, Chamberlain makes most, if not all, of Craftsman openers.

I have a Craftsman GDO #139.53674SRT2 recently it quit working. Neither of the 3 remotes work, or the wired wall button. When I press any of the transmitters or wall button the unit makes a click and then the orange light on the unit blinks 5 times, the light doesn't come on. The light does not come on when the beam is broken on the photocell eyes either. What do you think the problem is? I have checked the alignment of the photocell eyes and replaced the wired wall button, no luck, any advice?

don 1 2006. There was no way to cross the sensor wire pairs. The stiffness of the wire pairs was enough to hold their position while I lowered the opener to the latter to replace the gears. So I never gave crossing the wires a thought. Well after reading your comment I did go out and check and to my disbelief they were crossed. Reversed them and the sensor lights came on. Might have spent a couple days searching for obscure problems if it were not for your comment so I canÂt thank you enough.