Table lamp switches are usually designed in three different types. One is a do-it-yourself-friendly retro or antique lamp switch that comes apart with small screws; the other types include a modern sealed switch housed within a plastic case that does not come apart, and the socket stem switches that are common on the majority of table lamps. Lamp base switches, either rotary or push-button, are different from the socket-based switches of common lamps and are repaired differently. Although the retro antique base types and socket stem switches have a better opportunity for repair if they malfunction, modern sealed lamp switches can sometimes be repaired while not having to open up the case.
Base Table Lamp Switch Repair
Unplug the lamp from the wall outlet.
Unscrew the retaining nut on the switch. In most cases they will unscrew by using the thumb and the forefinger, but in some cases small pliers may be needed to exert more pressure on the nut.
Remove any backing on the base of the lamp. In most cases the backing can be peeled off and re-glued when put back on. You can also use a utility knife to slice through the backing to get at the switch.
Spray electric contact spray into the barrel of either the rotary switch or the push-button switch. Use the included straw that attaches directly to the spray cap. Guide the straw along the side of the switch. There will be a slight opening where the switch intersects the case. Do a half-second spray on either side of the switch at this intersection. The spray will penetrate inside of the case. Turn the rotary switch rapidly for about 10 turns or conversely, push a push-button switch up-and-down rapidly for 10 pushes. This will clean the contacts. Test the switch by inserting a bulb into the socket, plugging in the lamp and turning the switch on and off. If this is a plastic-sealed-case switch and it does not work after this treatment, it must be discarded and a new switch installed. If this is a retro switch that can be taken apart, go to the next step.
Unplug the lamp and remove the screws that hold the case together. Gently lift the top of the case off. On both push-button and rotary switches, there will be two copper contact fingers that are attached to the sides and protrude toward the center. At the center there will be a small circular wheel with copper-coated cams. With each push or rotation, one of the cams on the wheel will come into contact with one of the fingers attached to the side of the switch. Rotate the wheel and make sure a cam touches each finger in turn. If a finger is not being contacted, bend it outward slightly so it touches a cam when the switch is pushed.
Grease the entire mechanism with silicone spray grease if the switch turns hard. With the cover removed, spray a drop or two of grease around the rotary cam. Turn the cam several times to work the grease in. On many occasions, particularly on antique switches, the original grease dries up and the switch becomes hard or nearly impossible to turn. By adding grease, you lubricate the cam so it will turn freely and make contact with the copper fingers.
Replace the screws when the repair is complete, push the switch back into position in the base of the lamp. and tighten down the retaining nut.
Socket Stem Switch Repair
Unplug the lamp from the wall outlet.
Unscrew the light bulb, if one is in place.
Look into the socket. At the bottom will be a small round electrode that contacts the bottom nipple of the bulb. In some cases, the electrode is pushed in so far that it no longer makes contact with the bulb and the bulb will not light. Gently insert a screwdriver into the socket and slightly pry up the electrode. Replace the bulb, plug the lamp in and test the switch. If the bulb does not light up, go to the next step.
Unplug the lamp and remove the bulb. Next to the switch on the socket cover face will be a slight depression labeled “Press Here.” This is a latch on the socket cover that, when pressed with a small screwdriver, the cover can be pulled up to expose the inner socket where the wires are. Press on the depression and pull the socket cover up and away.
Check the wiring. Make sure the screws that hold the wires wrapped around the posts are firmly tightened. If a wire is broken or frayed, it needs to be cut back and stripped with a wire cutter and a wire stripper. Strip the insulation on the wire approximately 1/2-inch to expose the bare wire.
Wrap the wire around the post and tighten it down firmly with a screwdriver. Replace the socket cover by pushing it firmly back down and into place. Test the bulb in the socket by first screwing in the bulb and then plugging the lamp back in. If at this point the bulb does not light up, the socket will need to be replaced.