Hi, it sounds like either the door is actually locked into place or one of the door's rollers has come loose/came out of the track. That's happened at my mother-in-law's place several times...when she has one of the rollers come loose from the track, the door will raise about 24 inches and then stop, with the opener unit acting like it's hit the upper (opening) limit.

She also managed to lock the door down once by accident, using the original locking mechanism built into the door. We simply removed the two horizontal locking bars that extended into the door track, so that she couldn't lock the door from inside the garage. (She doesn't have keys to the original lock anyway, so no big deal.)

The fact that your unit appears to operate correctly when the door is disconnected from the unit, and I'll assume it worked fine before, seems to point to one of the two items I mentioned. Other readers will hopefully provide other possibilities as well. Good luck - let us know what fixes the problem!

Jim D/Heathsville, VA

See if you can easly open the door manually while the opener is disconnected.
If the door is working and adjusted properly it should stay open by itself when opened about halfway.
If all's well with the door operation, then get the opener fixed or replaced.

[This message has been edited by rpxlpx (edited June 25, 2002).]

Garage door openers have a "pressure switch" that determine how much force is required to raise and lower the door. It is possible that these switches have gotten out of adjustment. On the side of the opener where the lights are, there should be two plastic screws that are used to adjust the pressure (one for lift the other for closing). Try adjusting these (assuming that you door doesn't have some type of mechanical problem as suggested by previous replies). Good luck.