It sounds like a loose connection to me but you are right about the baffling. It would normally reverse to the open position whenever it is interrupted going down. I am really surprised this opener hasn't been replaced by now. The odds of getting 2 logic boards with the same problem is too high. I am including a link you can go to so that you can contact the manufacturer and explain your problem. They are without a doubt a number one manufacturer and I think they will help you.

Here is a link that might be useful: Help

don_1_2006

Thank you for responding to my post. I wondered about the odds of getting 2 faulty logic boards too. Unfortunately neither Liftmaster nor the folks who installed/serviced the door had ever heard of a problem like ours. Do you have any thoughts about Liftmaster's suggestion to try changing out the wall mounted controller?

Thanks for the link. And thanks again for replying.

Yours is such a strange problem that I guess anything is possible. The puzzler is that it just stops on the way down and according to your original post in about the same spot each time. I don't understand how the wall control could do it but Liftmaster knows much more about their openers than I do. I do think you should use the link I gave and contact the manufacturer. That way you can be sure you are talking to them and not to an authorized dealer.

Thanks for the advice. I sent them a copy of my post describing the problem. I don't know whether garage doors have gotten a lot more complicated, but our old Genie worked fine for many years. We only changed everything out because our old wooden doors were 'smiling' and the rollers slipped off the track with increasing frequency. Other than that, the motor and electronics worked great. Did we just get a lemon??