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.
Step 5: Make Use of the Threaded Portion
My fingernail points to the threaded portion of the nut that was removed from the rest of the nut. It no longer holds any parts into the power converter, but acts as a collar to keep the fuse centered and to reduce side-to-side play.
I did wrap the glass portion of the fuse with a layer or two of electrical tape so the fuse slides more easily and the edge of the metal fuse cap does not catch on the edge of the threaded portion.
Step 6: Assembled
There are a few spare parts left over, but the power converter now works reliably again. The metal tip that formerly made contact with the center tip of the cigarette lighter has been replaced by the end of the fuse visible in the photo. There is still a spring action on the fuse so that presses itself into the socket.
Step 7: Finished
This step is a bit of an update. In some cars, particularly rental cars, the power adapter did not maintain steady contact, causing the GPS to go to a blank screen and then restart or stay off. The flat end of the fuse does not make consistent contact with the center terminal in some cigarette lighters.
I stripped about an inch of #20 gauge wire and coiled a turn or two or three around the tip of a needle nose plier. I soldered the coiled portion to the end of the fuse. Then I clipped the wire. This leaves a pointed end on the fuse. Since we have had no problems with the power to the GPS cutting out in any car.