Summary

244 Hacking Electronics

There is nothing to stop us from taking such an adapter and putting a more standard plug on the end of it, or even connecting the bare wires to screw terminals.

Figure 10-7 shows the steps involved in putting a different type of connector, such as a 2.1mm barrel jack, on the end of an old cell phone charger.

The charger is of the “wallwart” type that plugs directly into an electrical outlet. The connector is of a type long since discontinued (Figure 10-7a). The charger has a label saying that it can supply 5V at 700mA, so the first step is (making sure the charger is unplugged) to chop off the existing connector and strip the bare wires. There should be two wires, and if one is black and one is red, then the red one is usually positive and the black negative. In this case, the wires are red and yellow. Whatever colors the wires are, it is always a good idea to use a multimeter to check the polarity (Figure 10-7b).

Remember to put the lead through the plastic body of the barrel jack before you start soldering!

You can then solder on a barrel jack plug (Appendix–code H11). This is much the same procedure we used for an audio lead in the section “Hacking Audio Leads” in Chapter 9. Figure 10-7c shows the plug ready to solder, while Figure 10-7d displays the final lead ready to use.

(a) (c) (b)

(d)

Figure 10-7 Attaching a barrel jack to a cell phone charger

Summary

In this chapter, we have discovered some of the treasures that can be rescued from dead electronic equipment and also briefly looked at testing and mending.

If you want to learn more about mending things, I recommend the book How to Diagnose and Fix Everything Electronic by Michael Geier (McGraw-Hill/TAB, 2011).