Step 5: Modify the Transformers
To open the chargers, you can use a variety of methods. I used all three of the following:
1. Find the crack in the transformer and pound at with a thin screwdriver and a hammer untill it cracks along the line.
2. Slowly cut the crack in the transformer with a utility knife.
3. Find the crack in the transformer and cut it open with a hacksaw
Find the + and - terminals of the transformer and unsolder the wires that were there. Resolder the wires from your DC Male plug onto the same points. Make sure you have the polarity correct!
Test the polarity with a multimeter, and if all is well epoxy the case of your transformers shut.
You can skip this step if your transformer already has the size N DC plug on it.