Speaking of electricity, the first thing to check if an opener doesn't work is the power supply. Is it plugged in? Are electrical wires loose or disconnected? Lots of household fix-its are just that easy.

                                    Tools & Materials

A door that fails to open fully can be fixed by adjusting the limit screws. Unplug the opener and locate the up-limit adjustment screw on the power unit. Turn the screw clockwise. Plug in the opener, run it through a cycle, and see if you need to adjust it more.


Eliminate a sagging chain by adjusting the chain tension. If the chain sags more than ½ inch below the rail, it may bang against the rail and cause undue wear on the drive sprocket. Tighten the chain until it rests ½ inch above the base of the rail, but be careful not to over-tighten.

Safety reversing sensors are those two little light-beam devices near the bottom of the door. If something breaks the beam while the door is closing, the sensor reverses the door. Sometimes, the beams can get out of alignment. Make sure the sensors face each other across the garage door opening in order to function properly.

Clean and lubricate the drive chain and track of the automatic door opener once or twice a year. Use a light penetrating oil instead of grease to keep from collecting dirt and grit.