This is a quick tutorial about soldering a mounted female jack that will accept a mono plug to a lead wire.
Not all jacks are created equal! It is important for you to know whether you're planning on plugging a mono or stereo switch to this jack. In this tutorial, we're intending to plug in a mono switch. We use the final product of this tutorial to switch-adapt toys, so they will function with external switches that will be plugged into the toy with a 1/8 inch mono plug.
Step 1: Understanding the Male Mono Plug
It's important to understand the wiring of a male mono plug to understand what we'll be plugging into our female mono jack.
Look at the image. Typically, there are two wires extending from the mono plug. Occasionally, there are three wires (as depicted in the image). The image represents a type of wiring where two wires (black and blue) are connected to the long terminal of the plug (it is also called the "sleeve" or "shield" terminal). In a typical mono plug, you will see two wires. One is connected to the shield, which is the longer terminal (in the image, this is the blue wire). The other wire is connected to the "tip" which is the shorter terminal (in the image, this is the red wire). In the mono plug, the "tip" and the "shield" are insulated from each other. But when the 'red' and 'blue' wires are connected together (through an external mechanism), then the 'tip' and 'shield' close the circuit. When we're putting together the female mono jack, we have to make sure not to short the terminals that come in contact with the 'tip' and the 'shield'.
Step 2: Understanding the Mounted Female Jack (with Lead Extension)
You need to identify the "tip" and the "shield" in the female jack:
You will see a longer terminal and one or two short terminals (the image shows a plug with two short terminals). Take a multimeter. First, just to demonstrate your use of the multimeter, make sure that the longer terminal and the sleeve are internally connected (by placing the multimeter leads to them and noting there is no resistance).
Likewise, one of the short terminals will also be connected to the sleeve (look at the grey colored short terminal in the image).
In the simple case (like this) where there are only two short terminals, the two wires (at one end of your cable) will be each soldered to one of the wires.
Please note that there are other cases that are more complicated as shown in the image labeled "synthrotek" where each jack has three short terminals. In those cases it is important to identify the "tip" and "shield" (and specifically to avoid soldering your cable to the "ring").
Step 3: Wiring the Extension Cable (lead) to the Mounted Female Jack
Make sure you size, trim and pre-tin your lead.
Identify (and label) which of the wires in the extension lead you will connect to the "tip" and the "shield" (if there are only 2-connector cable, there are no hard choices to make).
Take the mounted female jack. If you have a male mono jack, connect it to the female jack making it easier to hold (see images).
Thread the pre-tinned end of the wire from the center of the jack outward, through the terminal holes. Try to bend the wire so its ends lay flush with the terminals, and the insulated parts don't block the male plug (when it's plugged into the female jack).
Visually inspect and test your jack. To test, you can both plug in a mono jack and use a multimeter.
You are ready to use your mounted female jack!