Failing LA LED signs going to cost 20M to replace

"We bought a product with a 20-year guarantee that now needs to be replaced after two years," Villaraigosa said. "The public deserves an explanation, and I intend to ask the Department (of Water and Power) for one."

Alot more here...

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Re: Failing LA LED signs going to cost 20M to repl

It would seem that there are problems with many LED traffic sign implementations - I've heard that bad power supplies, poor thermal management, and EMI from the controllers are all major factors in the failures of some models.

Re: Failing LA LED signs going to cost 20M to repl

Yeah, probably one of those designs that some sales/marketing types rushed out of the door before proper testing/characterization was done, and just skipped the qualification phase, so they wouldn't loose the opportunity.

Re: Failing LA LED signs going to cost 20M to repl

You ever seen the components in a traffic signal controller? Big big contactors and other high-power AC equipment...

Re: Failing LA LED signs going to cost 20M to repl

Contactors? Like a relay or something?

Re: Failing LA LED signs going to cost 20M to repl

Contactors are heavy-duty relays - typically just NO contacts.

They're usually used for starting motors or other inductive-type loads that generate big arcs on startup.

Re: Failing LA LED signs going to cost 20M to repl

Some of us seem to be experiencing greater current consumption and less light coming from some of our older LEDs. A reduction of Vf was one suggestion for this. Could stop lights have a problem related to our LEDs?

Re: Failing LA LED signs going to cost 20M to repl

Those traffic lights need to be modded. Did someone say McTrafficlight?

Re: Failing LA LED signs going to cost 20M to repl

I wonder why the control mechanisms aren't upgraded to electronic when the traffic lights are replaced? Relays and the like are notorious for generating nasty voltage spikes.

Re: Failing LA LED signs going to cost 20M to repl

My experience in product design is that the things that go wrong are often much simpler. It is called attention to detail. The production guys are always looking for the least expensive way to do things, and often make changes that they don't think will make any difference. We built a product with a MTBF objective of 40,000 hours. Unfortunately one of the procurement/production people saw a way to save a few cents, and replaced the lamps we had spec'd for the indicators. Let's just say that the new lamps had a design life that was a lot less than 40,000 hours. They saved a few dollars on the power supply as well, with the same outcome. It took a couple of interations, and some very detailed discussions with the procurement and production guys to understand that there really was a reason we had some parts that seemed to be seriously over engineered. The system is only as reliable as the weakest link...

Re: Failing LA LED signs going to cost 20M to repl

Contactor is the term usually used for high current relays (more than 30 amps or so). Typically used for turning on very large loads. Wall switch activates the contactor, which actually handles the power. Most of them are just about bullet proof, and will take decades of abuse.