I can't recall the exact model number off of the top of my head, unfortunately, but if needed I can update with that later.

After reading a plethora of other posts about Craftsmen's openers I think I know what the problem may be, but figure while I'm at work I'd post the symptoms and get some second opinions from some of you folks who are leagues more knowledgeable in the field.

Yesterday my wife got home and on the way up the driveway hit the button on the remote to open the door, when she reached the top of the drive she found the door to have only opened up about 2 feet, and stopped.

When I got home I pushed the opener and the unit simply hums for a couple of seconds, briefly stops, then hums for a couple more seconds, indicating that it's trying to go up for a moment, thinking it has a jam, then trying to go down for a moment, but still not moving. So naturally my first instinct was that something was jammed. I checked the trolley assembly and I'm able to wiggle it around, it certainly didn't appear to be jammed on anything.

After this I disconnected the door from the trolley and closed it. I tried operating the unit again, only once again to get the aforementioned humming. I grabbed a ladder and checked out the unit. It seems when it was installed it was in such a fashion that the ceiling was too low so they had to do everything they could to get it to mount and not get in the way of the door. So upon inspection I found that the chain on the top of the motor doesn't have that plastic piece on the top, I forget the correct terminology. All there is is the chain out in the open on the chain wheel, and I could tell that it seems to have dug into the ceiling a bit. I took a flat head screwdriver and tried to pry it down, that's when I realized that it was just up there all willy nilly without that plastic piece that usually goes on the top of the chain there.

After prying it down a wee bit I tried to operate it once more, again only got the humming. At that point I fiddled with the limit knobs, turning them both a couple rotations in opposite directions. Tried to operate it again. This time the trolly actually returned to what would be the fully opened position, if the door was connected to it.

I pushed the button to operate it again and it went all the way to the closed position and stopped when it got to the door assembly that hooks to the trolley. GREAT ITS FIXED!! So I pulled the door up a bit to re-attach it to the trolley, hit the button to operate it....aaaaaaaand we're back to the humming and nothing else.

As I said - After having read a ton of other posts on hear about these Craftsmen (Should I say Crapsmen?) openers I believe it's the drive train that is shot.

Anyone have any other thoughts, or perhaps confirmation of my opinion?

Thank you for your time!