I've always had a few alarm signs scattered around the place, but they've faded to the point of being useless. So a few summers ago, I decided to get some new ones. These signs included a nice little solar powered LED device that you could attach to the sign's pole to illuminate it at night. Cool little things, they lasted all of a season before quitting.
The units are held together with 4 poor quality screws that had almost rusted to nothing. A rubber plug covered the switch. State of the fasteners notwithstanding, everything was still doing it's job of keeping the case sealed and debris free.
It's a simple circuit, the solar panel trickle charges the battery. A transistor turns the LEDs on at night, and I assume keeps the battery from discharging through the panel. The blue-topped switch turns the entire assembly on and off. This switch appears to be my problem.
I was able to jiggle it with the rubber seal off, and get the LEDs to light once more. Since it doesn't appear to be corroded, I'm guessing the thing is just of poor enough quality to not work. I could care less about turning it on or off, (why is this even needed? Who knows?) and the fix was to solderblob the pins together.
No more problems with bad switches, and something that should not have been there in the first place was fixed. My signs are lit once more.