This is a Garmin GPS for an automobile. The DC power supply for a cigarette lighter has been used by Garmin on quite a few models in recent years and is still in use. Ours has the nasty habit of coming apart so that the fuse and the center pin come out with the retaining nut. These small parts scatter throughout the car, and render the GPS useless, unless you want to see how long it will run on the AA batteries in the unit.
It gets worse. The retaining nut can be seen hooked over a piece of paper. The threaded portion of the nut cracked and separated from the rest of the nut. Before long the fuse will not stay in place, no matter what.
Step 1: The insides
I had forgotten, but this power converter had come apart once before and I had kept it together with a piece of plastic electrical tape.
Step 2: A simple solution to restore the converter
The first step in a simple way to make the power converter useful begins with cutting the rest of the threads away from the remainder of the nut.
Step 3: Solder a hook to the fuse
It is a great idea to have a fuse on the power supply, but these fuses almost never blow and need replacement. I cut a short piece of solid copper wire and soldered it to the end cap on the fuse. Then I bent a hook in the wire.
If you are concerned about blowing a fuse and not having a replacement, get a second fuse and solder a piece of hooked copper wire to it, too.
Step 4: Hook the fuse to the spring
I hooked the fuse to the spring behind it. This will keep the fuse from falling out of the end of the power converter. There is a space where the solid wire can fit without restricting anything and allow the fuse to move back and forth as needed.