Convert Belkin FM Transmitter from Battery Power to Car Power

Step 8 Clean up and final test

Now, make sure you cover all connection points (where you connected circuit board wires to charger wires) with electrical tape (just a tiny bit so it will fit) and figure out how to stick it inside the casing. I routed my charger cable around the outside edge and through the hole but it's a really tight fit. Now, put everything back together, both the charger circuit and transmitter and plug it in, hook up your mp3 player, and give it a go.

If it doesn't work, you should have tested everything before you stuffed it in! Take everything apart and check all your solder connections, make sure nothing is grounding together that shouldn't (insulate it with electrical tape), and try it before putting it together again.