Recently I fixed a Targus Universal Charger. This is the second time I have worked on one of these. If only I could remember what the problem was the last time, I could save myself lots of work. The symptoms are that there is no power at the output jack, and changing the jack does not fix the problem.
First I checked the power cable and it had power on the yellow main conductor to the shield. So it had to be the jack right? As you can see in the picture I tore the jack all to pieces to no avail. The actual problem is that the interchangeable jacks are ALL bad! They have to be broken apart and then re-solder the center connector to the circuit board. You might want to re-solder the grounds too while you are in there.
The connection color code from the end with a metal plate is: