Thanks for that.
I saw your thread, I hope you can figure it out soon. Mine was sort of a fluke, so I'm not sure anything about it is applicable, but just in case... The bottom line is that when I was first attaching the COB holders to the heat sinks, I was standing over them and tightening them until they looked flush. The next day I had it propped up on something and was looking straight across at it, and with a window behind it I could see a tiny sliver of light between the COB and the heatsink on a couple of them. While trying not to over-torque the set screws the night before, I ended out not fully seating them. Once I did that, plugged it back in and everything lit up. There are a handful of things that can go wrong, that was (the first thing) that wasn't right on mine.
It can be frustrating when you put all that time into it, plug it in, and then nothing happens. For me, the hardest part is that I'm copying peoples designs without a full understanding of the underlying principles. That means that as long as I copy carefully and everything goes as planned, I'm golden -- but as soon as something goes wrong, my ability to troubleshoot is very limited. Luckily there are only so many components to the system, so there is a limit to what can go wrong.
If I ever build a big light with lots of COBs, I think I would use multiple drivers so that if/when I have issues, it is localized to a section of the light and that narrows down the search for the cause.
