Thankfully the unit has a UL certification. Therefore, there was never any risk.

Sarcasm doesn't come across very well on the internet. Neither mine, nor your's.

Whaat you all have identified is what us engineers know as a "dirty litle secret". Now that it has seen the light of day, it will be interesting to see JJP's reaction. They will either be proactive, or deny it's a problem until the insurance company goes after them. Perhaps the board is contained enough that there will never be a fire claim. I guess that's the best case for all parties.

BTW, what does that replacement board cost if you just want to order one?

"We know every serial number that has" the problem, but we aren't bothering to take care of them until they make noise.

I wonder if that is related to the problem or only indicative of the production lot. It seems the extensive record-keeping might have experienced a glitch in the case of these boards.

Serious question: How does higher and higher frequencies impact the engineering challenges other than in the parts that are specified or designed? Once you cross the visible/audio frequencies, isn't it all beyond direct human observation?

I guess from a technical standpoint, I don't understand your "humbling" description.

A sincere thank you for your comment. I guess I'm still missing your point. Obviously an aborigine would bow to a cable guy who showed him a smart phone for the first time. But aren't the crazy technologies you are justifiably impressed with simply another application of cutting edge semi-conductor technology? You obviously have a technical background that exposes you to these advanced technologies to which you refer and I have a tendency to over-simplfy every complex system of which I am aware.

I once told a micro-controller programmer I knew that I didn't understand what the big deal with programming was: You get a little input, you process the input and then you give a little output.

Even though this is a gross oversimplification of almost anything practical, the process is simply assembling and organizing constructs of existing technologies to acheive some goal. Now while I agree that the inventors of the technologies to which you refer are the ones to be humbled by, I have found that most engineers implementing known and documented technologies and components are mostly just specialized students of very specific technologies that any reasonably gifted engineer could pick right up on given the task. Perhaps I am confusing the people to which your comments refer.

I learned a long time ago that when anyone over-complicates an area of expertise, it generally becomes more of a psychological play than a scientific one.

I must admit that I really have know idea how these powersupply boards work, but I can smell bullshit a mile away when it comes to a component failure this extreme. A proper failure mode and effect analysis (FMEA) walk through is needed on this board. Perhaps SMT is inappropriate for a power supply used in this fashion. I'm pretty happy whenever I get to work on a 35 YO monitor chassis with the large, hand-drawn traces on only one side of the board. If the relatively giant solder blobs on those things are cracking, it makes you wonder how those thousands of tiny solder joints are holding up after just a few years.

Has the coil been under-specced or produced out of spec, or is the coil failing because of ancilliary components in its circuit? Perhaps one of the SMT components is borderline and heat cycling to cause a mechanical failure of the surface solder and in-turn is asking the coil to do something it was never specced to do. My suspicion is that the coil is a symptom and the design is the disease. This may all comes down to one of those "dirty little engineering secrets" that may never see the light of day. In the end what really matters is JJP's response to the problem and I think the jury is still out on that. I'd say things are looking pretty good right now, but there were a few warning signs early on.