Dave Jones got some burned LED light bulbs in his mailbag.
He gives an interesting study of how they failed. It turns out that it was a thermal issue rather than a component issue. My question is why anybody would produce stuff that certain to fail. Now if there were large assembly or component cost issue I could understand it, but the LEDs and resistors are going to cost within 1/10ths of a cent of each other and the bulbs are probably machine assembled. So the issue has to come down to design. I suspect that one problem is that it’s so easy to get Altium and make up a simple board like this. And if you print out the board and light everything up it works just fine, for a while. The design may have even been fine with the more expensive PCBs used for the prototypes. Which was the same PCBs the first few batches had.
Here’s where culture rears it’s ugly head. Here in the US, more than likely, if somebody made bulbs like these, the quality would remain the same and not change. The US is a high trust society for the most part and people try to keep their commitments. There’s also 200 years of “that’s how you do business” in the US and the Western world. People have learned the hard way what happens if you don’t and the stories have been around forever. In Japan, when they started to industrialize, quality fit nicely into their culture, which reaches deep into “doing your best even when it doesn’t show.” China though, doesn’t have that culture. China, historically has been a low trust culture, run by a professional bureaucracy. Who behaved like bureaucrats always do. And businessmen were lowest on the status scale and bound up in red tape. So the Chinese haven’t developed the deep trust in each other that doing business remotely requires. And they are new to learning that now.
Now I imagine that the people who produced those LED bulb didn’t think it mattered that the cheaper PCB’s were used. That probably increased their razor thin margins just a little. I also suspect that their was some person who rejected the parts and sent them back, correctly. The bulbs probably had SCRAP on them at some point. But somebody, brought up in a culture of scrimping for any advantage, living on a razor’s edge decided to sell the bulbs on Ebay. After all they worked. The fact that doing that only reinforced the reputation for Chinese low quality and made future business that much harder, never occurred to them. That’s because, in a low trust society, you live for the moment, because it can all come crashing down on you at any moment. That’s why the bulbs went bad.