Transistor Radio Time Machine

Step 11 Hook Up The Thumb Switch

On most older transistor radios, there is a second thumb wheel that controls on/off and volume. You can hear a little "click" as you rotate the wheel to engage the switch. We're not going to use it for volume because the impedance of the radio potentiometer is usually not a good match for the new sound board. Anyway, the sound board puts out just the right amount sound for the speaker. Locate the two outer terminals of the potentiometer/switch that is attached to the thumb wheel and confirm that they are connected to the switch. On one of the two terminals, solder the red wire coming from the battery holder.

Cut and strip an 8 inch piece of red wire and solder it as well as the other red wire connected to the sound board to the remaining terminal on the thumb wheel switch.