How to replace a lamp holder, the tips as following: Most table lamps consist of a body, a lamp holder where the cord enters, a harp to support the shade, and a table lamp holder, which receives the cord at one end and the lightbulb at the other. The cord usually runs through a hollow threaded lamp holder.
When a lamp won’t work and you know the bulb is OK, check the cord for damage. If the insulation is worn and cracked, replace the entire cord (see Rewiring Lamps, Related Projects). If the cord is OK, the problem is most likely in the lamp holder.
A) Unplug the lamp and remove the light bulb.Start by pushing the lamp cord through the 1/4″ hole toward the bottom of the base. Obviously, you want the plug on the far side of the cord and the bare wires to be pushed into the 1/4″ hole and into the center of the porcelain socket.
B) Unscrew with your fingers the filial or decorative screw that holds the lamp shade in the lamp harp. Remove the lamp shade. Place your fingers on the harp sides where they start to bend up around the light bulb area on the lamp. Squeeze the harp sides toward each other with your fingers to get the ends of the harp, called the legs, to pull out of their slots or seats on the lamp and remove the harp.
Most lamps have felt lamp holders that must be removed before repairing the lamps.Loosen the set-screw on the lamp socket base. Unscrew the porcelain lamp holder and remove it.
C) Pull the wires out of the lamp gently. Unscrew the wire terminals with a screwdriver and unhook the wires. You will notice that the wires are knotted — leave the wire end knotted; this prevents the lamp cord from pulling up and out of the lamp during use.Reassemble the porcelain lamp socket carefully and make absolutely sure that the wires only touch their intended screw and do not touch any other metal. And make sure there are no bare wires that extend outside the metal base on the porcelain lamp socket.
Finally, double check that you have the ceramic washer that is installed in-between the wiring on the bottom of the lamp holder and the metal bottom piece. Reinstall and snug the two phillips screws from the bottom of the socket where the bulb is installed.
Remove the felt by paring it off with a utility knife. After the repair, reapply the felt with white glue.