Well my issues with the driver from earlier seem to have been resolved I figured out the problem and fixed it. If you didn’t see that thread I have built an Convoy L2 with an MT-G2 on a Noctigon and a LCK-LED 5A driver.
Anyway the light is working great but there is a small black dot in the centre of the beam. What causes this? Is it because the LED isn’t sitting far enough into the reflector?
I have attached a picture to show you what I mean. I have played with the contrast a bit to try and get it to show up better.
I’ve seen something similar on a P60 smooth XML reflector, fairly annoying and didn’t find a way of fixing it.
I assume you can’t get the emitter into the reflector any further? Maybe try shims to pull it very slightly out of the reflector and see if you can get a better focus. It probably wouldn’t take much.
Many good throwers have a hole in the middle at close range. It is commonly considered at sign that you are in focus (or close to it) when you have this hole. Generally, they are bigger than in your picture. So you may be not quite in focus. Or you might be right square on in focus. The hole may be small due to the large emitter you are using.
The distance would probably be about 4m. It doesn’t disappear with distance unfortunately, I can see it when using it outside at a much greater distance.
However it appears I may have shorted out the emitter now :(. On a side note what is the easiest way to check if an emitter is dead?
'Diode test' mode usually doesn't give consistent results when testing LEDs. Make sure neither pad is shorted to ground, then apply a known-good voltage. Two 3v CR123s work well for the MTG2.
I have shadowy black spots on most of my MTG-2 lights in the very centre of the hot spot as well. All have different reflectors. On my lights its only apparent white wall hunting. Outside in actual use I don’t notice it, but then I’m not looking for it then either.
Could this be an artefact of the multiple small emitter segments on the die?
Kind of like true multi-die cross artefacts but less pronounced?
A low moon mode and a light with a large reflector can be a great combination to study how various parts of an emitter’s die surface are bounced around.
Another is a light built by a guy in the other forum, using a T10B host from IOS. I heard that he spent some time working on the reflector so that it fits “perfectly” with the MT-G2.
Both of the above lights have MT-G2 on Noctigon (again, from IOS), and I just checked and they don’t have a black spot in the beam (just checked on white wall, but now I’m like half blind :laughing:…
Try looking at the emitter through an Arc-Welding mask if you can find one or have one.
(better if you can do it on a low mode)
that way you can safely look at the emitter surface and the reflector through an ArcWelding mask filter with being blinded or damaging your eyes, and see if there is any dead spots on the emitter surface or any irregularities on the positioning of the emitter, or irregularities in the the reflector.
(I have used my welding mask filter many times to inspect emitter surfaces when on to see the patterns.
Ok, so now I am really confused. I powered the MT-G2 directly using two CR123As and it worked fine. The driver is supplying 8V to the emitter leads (batteries aren’t fully charged) however the driver won’t power the emitter? It was to start with then stopped suddenly last night and now it is doing as I have described.
That is a good suggestion. I don’t know how to delete the old thread so I will just leave that one and continue here.
I’m not sure if you are familiar with the Convoy L2 host but it does not have a removable pill. The parts are assembled inside the head itself, which is actually quite annoying.
Anyway here are some pictures. Drilling the holes in the contact board has actually been the most useful thing so far. It allowed me to position the contact board much closer to the driver and also connected the power directly to the spring and directly to the earth ring.
The positive wire you can see circled in red and the earth wire is circled in black. There is copper braid in the centre.
