My Sears 1/2 horsepower garage door opener has quit working. Upon inspection, when if start the opener the motor turns and the main gear (attached to the motor axle) revolves but the secondary plastic gears are unengaged and there's a pile of fine white powder on the bottom of the cover. I'm guessing the powder is dried grease and not ground up plastic from the gears since they're not stripped. Any ideas on what's wrong and how to fix it? Unless the problem's electrical, would replacing the gears do the trick?
It sounds like the driven gear has a stripped spot on it or has somehow moved out of position :confused:. The stripped spot may be hard to spot because of the drive gear blocking the spot it would be striped the rest of the gear would look fine and that would be the gear not moving so the spot would remain in the same concealed position. Replacing the gears may fix the unit but some units develop other issues with the drive mechanism for the up and down shut off triggers and this or other reasons may have caused the original failer.