Michael A. Terrell wrote:

D Peter Maus wrote:

Michael A. Terrell wrote:

I used to work with someone who now works for the county technical
department. I'm going to see if I can get my hands on some bad LED
traffic light assemblies to do failure analysis.

Excellent. Post your results, if you don't mind.

No problem. I'm mainly interested in the power supply, since strings
of about 12 go out at a time. I want to find out if its a crappy SMPS,
ar maybe a couple to reduce the chance of catastrophic failures. Now,
all I have to do is get my hands on some samples. I may try contacting
Florida DOT. If they are rebuildable, I am looking for a few projects to
create part time jobs for local Disabled Veterans. I'll bet that they
can replace bad capacitors and LEDS after they are troubleshot.

The first generation of LED traffic lights in my area started to fail in
about a year. It looked like there were random failures of each LED
element. I didn't notice if they were part of a string. The newer LED
traffic lights are lasting much longer. I've also wondered why the new
sodium street lights seem to have a shorter life than the mercury vapor
ones they replaced. The opposite is supposed to be true. The sodium
lights can be a serious source of RFI when they start to cycle on and
off at the end of their life. Some people think they have the ability to
make the sodium lights go out when they're near them. It's really just a
coincidence but you can't convince them of that. If you do a Google
search for 'street lights turning off' you'll find all kinds of
testimonials, including paranormal explanations.