[mikethedruid]

This evening I tackled the tone control. It is an interesting little gadget, with a steel frame formed into a box at one side, and a 2 position switch with a 1/4" shaft which rotates a brass sliding contact onto and off of an insulated contact. The shaft and slider are grounded to the chassis, naturally. In the box there are two condensers, a 0.02 mfd and a o.002 mfd. They both connect to a lead going to the audio output tube. The other lead of the 0.002 mfd is directly grounded to the case of the little metal box part of the steel frame. The 0.02 mfd condenser's other lead is connected to the insulated contact, so that the slide contact connects it to ground or disconnects it, depending on position. Very interesting and simple design. I like it.

I melted the tar from the box housing the two condensers, and replaced them. I lubricated the shaft, and re-peened the end of the shaft that secures the brass sliding contact. The unit now functions well again. I then wired it back into the receiver.