I think you will find the trolley (the thing the chain is attached to) is jammed against a bolt in front of the motor unit. Remove the bolt and then locate the 'up limit' control on the side of the motor unit. Using a small screwdriver, turn this control 3 or 4 turns in the opposite direction of the arrow printed on the cover. Be sure to replace the bolt. This should take care of your problem.

Don

Thanks for responding Don. I checked the trolley location and it is ~6 inches from the bolt that you are referring to so I don't think there is any jam there. Any clue as to why the lights wouldn't come on even if it was a motor-related hang-up? That symptom would make me think it is something related to the power logic circuit. I'll go ahead and try making an up limit adjustment anyways. Do you know how I could get a circuit diagram...perhaps even a generic one? My model# is 139.53675SRT2. Thanks!

The manufacturer hasn't supplied a schematic on these things since the labor rates got so high it was cheaper to replace than diagnose.

Get the part number off the end of the unit where all those white wires go. It starts with 41 and then call your local shops and see if they possibly have a used one they will sell. They change these door openers out constantly and save the old good parts. You might make a deal.

I have the same problem as above.The amber light on the side of the main unit flashes five times and then repeats this five-flash sequence. The door is in the closed position and will not open. I saw another posting on a help site that said that this flash code is activated due to a motor overload or RPM sensor problem. I think my problem might be different though. I unplugged the main unit, plugged it back in and the amber light clears. Then, when I press the light button on the door remote I hear a (relay?) click in the main unit but neither light bulb comes on. Then when I press the door open/close button on the remote, I hear a (relay?) click, and then the five-flash sequence on the amber light starts but the door doesn't move.

Jason, sounds like you have a bad capacitor.