Thanks for the suggestion. Visually, the limit switches look alright. When I manually place the 'locator' to the bottom (resting up against the lower limit) and then activate the opener, the 'locator' travels up the center screw until it makes contact with the upper limit and shuts off. When I activate it again, only get a 'click'. Specifically, what else should I be looking for on the limit switches? It makes sense that the logic board may not be getting the correct signal. Once again, thanks for your assistance!

Well, rather than a repair, I just moved into our house (3 years old) and the third car opener has never worked right. It initially would go up, but not down, and didn't stop at the top, it just jammed and vibrated against the opener unit. I opened it up to find that somehow the open adjustment stop was bent and the locator just went right by it and kept trying to go up. I righted that situation by bending the stop back and setting the open travel adjustment properly. So now, it will open, and when hitting the stop, does stop. But, it will not close. I can manually close it by removing the belt from the motor and getting everything set at the bottom, then push the button and it opens again and stops properly at the top. Holding down the button does no good, and I can confirm the photo sensors are aligned properly because if I block them, the opener lights come on. It just seems to me that whatever switch exists to tell the opener it is at the top and needs to reverse direction has failed, but I have no idea what that is or how to fix it. I did find the start capacitor you guys were talking about (big blue guy, 4 wires, two red, two blue). My terminals are top and bottom, with connections on each side of it. The reds are on the bottom, and the blues on top. My opener is model 139.53954. Thanks for helping.

Hi adilss, kudos for you fo rstarting your own thread instead of piling on another! That is why I am answering you. This is rare, but can happen, most of ten in winter. It seems the ambient light overwhelms the receiving eye and drowns out the signal from the sending eye. Try taping a toilet paper roll cardboard around the recievr eye. Then make sure the "eyes" point right at each other, then see if it closes with the remote. Or try closing the door by holding the wall button down, release trolley rope, and move the trolley back up to the up position, leave door closed, and try to move trolley down with a remote. if it works, teh probelm is overwhelemd receiver eye. Sheld it with carboard tube from tp or a small flat shield so sun doesnt hit the recvr eye, or swap receiver for sensor, or check very carefully for flickerign receiver yee with door closed. Good luck

Make sure the black cap is on the back of the motor shaft and pressed all the way on. Make sure the 4 pin circuit board next to that black cap is plugged in. If neither one of those two are the issue and you replaced the worm gear as well, what you will need to do is loosen the coupler up on the back of the motor shaft. On the front of the motor (door side) where that shaft pokes through, push it back as far as it will go and hold it there while you tighten the coupler back up. One of these three problems is always the issue for people who have done this repair themselves.