I recently swapped an MT-G2 into a BLF D80 host and unfortunately the hotspot has an artifact (dark spots) right in the center that looks sort of like a radiation symbol.
Is this common with this emitter, or did I simply get a dud? I haven’t found anything helpful with Google, so I’m not sure if I should have expected this.
Would an OP reflector help the center of the hotspot? It it simply a byproduct of not being perfectly centered in the reflector?
The MT-G2 has 4 dies, with a slight gap in between them, the gap between the dies is what produces the shadow in the beam, i.e. it’s like having a big die with a dark cross in it. The only way of getting rid of that die is to defocus the beam, an OP reflector can do that for you.
I’ve got an XHP50 which is similar to the MT-G2 (almost it’s spiritual successor) and am expecting similar problems when I put it into the host I have for it. Let me know how you solve the problem so I don’t have to go through the same pain!
:EDIT:
It was the MK-R I was thinking of here 
Actually, quite the opposite. The reason the mtg2 is so liked is because it doesn’t suffer from the same shadow that the xhp50/70 suffer from. The mtg2 isn’t four individual dies so much as just one really big one.
I figure your problem is with centering. As always, pictures will help.
Not that I know what I am talking about, but if the spots are right in the center could that indicate focal length issues rather than centering?
Nope…no gap in the MT-G2, you may be thinking about the MK-R.
Is it just when you’re white wall hunting or is the donut hole there at distance?
You’re right about there being no gap on the MTG2. I’m guessing I’ll have to figure out how to deal with the XHP50 on my own!
The MT-G2 is actually 72 tiny little dies, iirc. They’re not always perfectly even though. I’ve had MT-G2 lights that had slightly dimmer “spots” in the emitter, but its usually only noticeable at really low output levels. More likely any sort of ring or artifact is an issue of focusing in the reflector.
OP reflector and/or sanding the dome. I think those are the best ways to get rid of that shadow.
Did you clean the dome? Is there debri or damage on the dome? Remove the reflector and lens and check for it against a wall, bring the levels up from low to high, is it still there?
I solved that on my XHP70 build by using a faceted reflector (Ledil Boom) in an S2 host:
I should have started there….
Centering (not perfect, I realize):
Beam shot with reflector, you can see the dark spots here (not sure what the smear off to the left is, I think it’s an odd patch of paint on the wall, not sure):
Focal length? Does that apply in the case of a reflector? I don’t know.
Mainly white wall hunting. I went for a walk tonight, and honestly didn’t even notice it, but it still irks the perfectionist in me…. It’s more like spots/speckles, rather than a donut hole, I’d say.
It’s noticeable at all outputs, at least on a white wall. It’s pretty difficult to notice outside on uneven surfaces. This is the bare emitter on “moonlight” on the FET. It appears to be pretty evenly illuminated to me, but I’m a complete noob.
The dome never got dirty, it’s brand new, undamaged. This is how it looks without the reflector. I can’t notice anything with my eyes unless the head of the light is nearly touching the wall, but I’m not sure if that’s what I’m seeing with the reflector in, or what:
Less exposed:
Easy solution: Use the light on something that’s not a white wall.
MT-G2 have always shown dark spots in the beam. It can be gotten rid of with a OP or stippled reflector or sanding the dome on the led. I just did another MT-G2 Maglite and I sanded the dome with 1500 grit and then stippled the Maglite led reflector and the beam is perfect. Large hot spot, but no dark spots at all.
classic
Actually I’d +1 and agree with this.
One of my MT-G2 lights has some dark spots in the hot spot. I’m sure it’s down to the construction of the MT-G2 and all the dyes it has.
But you can only see it when holding the light still on a white wall. Using the light outside you simply can’t see them, even if you look really hard for them.
I usually get a little splatter when I solder leads on the mcpcb, specially the 20mm boards, some times I find solder on the dome? Now I tape it up with painters tape before hand. I also like to chamfer the back of the reflector emitter hole with a 45 degree bit, large enough so the reflector self centers itself on the led pad.
Agreed. Its like my C8, I can only see the yellow in the centre of the XPL-HI beam against a white wall up close.
But I guess us light fenatics white-wall-search all the time, to check for such annoying imperfections.
Your every day user would not give 2 hoots about a less than perfect beam. We do and that’s a good thing.
Didn’t mean to abandon this thread, got caught up in school work last week.
Well I suppose that’s one way around it. I took it camping this weekend, and didn’t notice it at all outside, but it’s still one of those things that kills the perfectionist in me….
I’ll probably end up trying to sand the dome a little. I think I’ll leave stippling the reflector as a last resort, since I don’t imagine replacements for the D80 are easily available, and I’d hate to screw mine up. I’d probably try fitting a Ledil Minnie reflector first. Thanks for the suggestions.
Seems likely.
That was my experience as well, that it’s pretty difficult to notice outside. It’s still somewhat noticeable indoors, but 1) I know it’s there, so I’m looking for it, and 2) it’s shining on things closer than outdoors, which I’m sure plays into it.
Ah, okay, I see where you’re coming from about the dome being clean. I fortunately didn’t run into that issue, but the dome on the XM-L2 that came in the light had a couple specks on it, which very well could be exactly what you mentioned.
Chamfering the back of the reflector sounds like a really interesting idea. I’ll have to keep that in mind for other projects. This reflector is aluminum, and I’d hate to drill through it or knowing my luck, the bit would bite and warp the whole thing or something.
Well considering a Maglite is the ‘gold standard’ for pretty much everyone outside of our little eccentric circle, I’d have to agree they wouldn’t give 2 hoots about a less than perfect beam, lol.