The information presented on this page is for 1937-42 Philcos; however, it can also be used for other applications as well.

Parts Needed:

• One #6 nylon washer (Mouser Electronics part number 561-D662, also available at some hardware stores)
• Heat-shrink tubing, 1/4″ diameter
• About ten minutes’ worth of time

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Above is a pilot lamp assembly from a 1940 Philco Model 40-185. The insulator used in this lamp socket is made of rubber, inside the spring which holds the bulb in place.

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When pulled apart, you will find that the rubber has melted into the spring in Philco lamp sockets made between 1937 and 1942. You will need to remove the rubber from the spring before proceeding.

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After the old rubber insulation is removed from the spring, move the spring back out of the way. What you have left is a rivet, to which the wire is soldered, and a thin metal washer behind the rivet, as shown here.
Unsolder the wire and keep the rivet. The thin metal washer may be discarded as it will no longer be needed. Set the spring and the pilot lamp shell aside for now.

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Cut a length of new wire to the same length as the old wire, then discard the old, rubber-covered wire.
Here is a close-up of the new nylon washer which we will use. This is necessary to not only allow the spring to hold the pilot lamp in place, but also to insulate the spring from the rivet. A metal washer would cause the lamp assembly to short out, which could also cause the power transformer to burn out. We don’t want that to happen!

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Strip about 1/16″ of insulation from one end of the new wire, and insert this into the rivet from the back (narrow end), as shown. Solder the wire to the rivet at the front (wide end) of the rivet.
Do not allow a large solder blob to form on the wide end of the rivet; this will not allow the lamp to be inserted into the socket when you are finished.

You may need to smooth off the wide end of the rivet with a file to obtain a smooth, rounded surface. This end will make contact with the end of the lamp.

Cut a 1/2″ length of heat-shrink tubing, and get your nylon washer ready.

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Slip the heat-shrink tubing over the other end of the wire, and slide it up to the rivet. Using a heat source such as a lighter, match or heat gun, carefully heat the tubing until it shrinks to cover the narrow end of the rivet, as shown.

It is important that your joint look like this at this point, as you do not want the spring to contact the end of the rivet or any part of the wire where the insulation has been stripped off, else a short will result.

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Now slip the new nylon washer over the new wire from the opposite end, and slide it up to the end with the rivet and heat-shrink tubing. Slide the washer up to where it makes contact with the rivet, as shown here.

At this point you are nearly finished.

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Slide the other end of the wire through the spring, and through the pilot lamp shell. Your lamp socket should now look like this.

That’s it! Strip a small length of insulation from the other end of the wire, solder it back into the radio where the old wire had been soldered to, push everything back into the shell, and install a new lamp.

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The finished product is shown above. This repair should last for many years. The nylon washer will not break down, as the old rubber insulation has done over the past several decades.