What happened to my Lux3? It flickered and got dim

I was playing with a new mod someone sent me. It was a Lux3 driven by 2 nimh AA's. I turn the sucker on and gasp in amazement at how bright the beam looked. Then about a minute later the light flickers some and gets dimmer and dimmer. What the heck happened? I let the light rest a bit before turning it back on. Now it does light up, but I swear it's not as bright as it was initially. Did something bad happen and is there a way to make it brighter again? I assume it didn't burn out because it still lights up, so what did happen?

I guess the LS was severely overdriven. This had happened before on 5W emitters, but it's new for a 3 watter. In the 5W case I believe some cracks developped on the die that eventually lead to partial failure. There isn't anything you can do except for changing the LED and adding some resistance to prevent this from happening again.

It was only driven by two(2) nimh AA's. A 3 watter can be overdriven that easily? And it can still light up after a partial failure?

edit: btw current was 667. Does that matter? It was one of those Arc LS mods.

Disconnect all pieces and clean all contact surfaces.

Also, check batteries for condition, you could've had a short....

Hope that works for 'ya.
p.s.-what kind of mod did you have?

were the batteries low? it could be out of regulation now... I'd think 667ma output would require at least 1 amp draw off of the batteries and probably run them down quickly...

Oops, just editted above post before seeing your question. It was one of those Arc LS mods made to run at 667 and useing a lux3 and a fraen.

I'm a newbie, so here's the most basic question. Is the thing screwed up? Do I have to replace the Lux3 now? Can the Lux3 still be used or is it garbage now? It still lights up, just not as bright.

1800 mah batteries, had them charged and sitting on a table for two weeks now before using them.

Before concluding that the LED is bad, try using a pair of fresh alkalines in it.

(edited to correct for dyslexic syntax error) /ubbthreads/images/graemlins/icon15.gif

I'm missing something here, but from what I caught, it seems that maybe we're talking about a Mini M@g mod or something similar running a boost converted. If so, do clean all contact surfaces, then check for shorts. You might need a magnifying glass to do this. You'd be surprised at how small a piece of metal or conductive material can cause a short.

Vcal: it still lights up nimh's, it just doesn't seem as bright anymore. I just tested with fresh alkalines and don't see a difference. So are you saying the fact that it lights up at all means it's not damaged?

Chop: It is not a Mini Mag. It is a Arc LS modded with a Lux3, fraen and boosted to run at 667. So how do I lean the contact surfaces and check for shorts? And assuming what happened was some sort of short, does that mean the Lux3 is now damaged?

I'm trying to figure out if I need to have the Lux3 replaced now. /ubbthreads/images/graemlins/frown.gif

[ QUOTE ]
Sinjz said:
Vcal: it still lights up nimh's, it just doesn't seem as bright anymore. I just tested with fresh alkalines and don't see a difference. So are you saying the fact that it lights up at all means it's not damaged?
I'm trying to figure out if I need to have the Lux3 replaced now. /ubbthreads/images/graemlins/frown.gif

[/ QUOTE ]
If there's no improvement after cleaning all of the contacts and battery change, then it's either the LED -or the boost circuit itself.

I can't think of any other possibilities. /ubbthreads/images/graemlins/frown.gif

I had this problem with my first Arc-LSP mod @ 667ma with luxeon3. It turned out to be the LT318chip which I replaced and got it fixed. First off, try new alkaline batteries, If it's still dim you might want to check the solder joint connection of the two leads(anonde/cathode) of the 3watt emitter to the circuit board. In order to make a good solder connection these leads must be pressed as you solder it to the circuit board this assures proper solder binding to the board. I noticed this problem with my arc-lsp as I was replacing the the LT318 chip /ubbthreads/images/graemlins/banghead.gif

are you using a twistie with the Arc, sometimes if you turn too much you might crush something on the board.

If it's a Arc mod then the LS-III is probably OK, but the boost IC or the inductor may have been tosted. They are working extremely hard, over their rated conditions, in those 667 mA mods.