How to remove AA glued LS emitter?

I have changed the emitter on ARC LS. Original one was kept on board by the sticker but I used the AA epoxy for new one. I have an Q3J bin on board now but decided to change it to LS III together with boosting the circuit. (ARC4 sec. arrived).

Does anyone know if there is an easy possibility of removing the emitter once epoxied from board without damage of both?

Second possibility would be someone to offer another ARC LS for modding /ubbthreads/images/graemlins/smile.gif

If i were you, i would leave the Q3J alone.


But if you insist on removing it, i can suggest some (not so safe) ways.

1. you can try removing the lux by using a small screwdriver and pressing the dome down to keep the dome intact. Drawback is if you DO manage to remove the lux, the dome will be dirty (can be cleaned though) and this way does not have that high of success rate.
2. You can just straight remove the lux using plier, but that is about 99% killing the lux.
3. you can try bore some metal at the bottom of the lux and use screwdriver to remove the lux, similar to the first method. Drawback is, you can possibly manage to break the circuit itself.
4. You can try heating the board and hope that the AA loosen down, so you can easily remove it. Drawback is you can possibly melt the lux along with the board if the heat is too much.

Again, if you already epoxied the lux with AA, it is best to let it be. may i know why you would want to do that in teh first place? I thought the solder pad enuff to keep the lux in place, with the pressure of the optic enuff to keep the lux to touch the heatsink. /ubbthreads/images/graemlins/icon3.gif

Yeah, the AA wasn't necessary. I would keep the Q3J there, since that's a pretty nice LED as is... you probably won't notice the difference between that and the lux3 if the color is ok with you...

You can do the current mod w/o removing the lux...

Thaks for all the warning. I am going to leave it. Too much risk.
I thought somehow that AA would be better to keep the emitter because the thermal sticker looked worn out. Now I know I should have put this q before doing the Q3J swap. /ubbthreads/images/graemlins/frown.gif

TheFire - how much current increasing is safe for lux1? I remember there was some page to calculate resistor values, right?

cosco, it depend on how you define safe. Lumileds' term of safe is 350 mA, which is what arc runs their lux at. But for us, 350 mA is puny current. I think 700 mA is pretty much safe, given enuff heatsink. 1 amp is pushing the limit and 1.5 amp is killing the lux. good luck.

Btw, increasing the current in the ARC is not gonna be simple V/R calculation.

You could try to use nailpolish remover, but be careful not to mess up the circuit! /ubbthreads/images/graemlins/wink.gif
(credits for this method should go to kakster /ubbthreads/images/graemlins/smile.gif )

I should point out that it will likely kill the electronics. Certainly ive never used this method to remove anything and have it still work afterwards. Its just a way of removing AA without scratching the hell out of the bezel/heatsink.

The story behind is I got an ARC LS second as my first ARC and was itching to upgrade it to better bin. I had not any lux3 around. They sell only ls1 and ls5 here in local shop. The advantage is I was able to find nice bin in the bunch of stars. I know I should have waited. After swapping emitters I went across dat2zip offer of good bin of ls3. Now I am pretty sure to spare it for another mod.

As for the resistor values on ARC board. I think it is the same design as MadMax. There is a pad with ,15R and another empty one. If I add another ,15R it should boost up to 665mA, right? And if I use smaller value then ,15 for another resistor, it should boost more then 665, if bigger then less then 665. Is that correct?
Do you think ARC LS is able to heatsink the circuit boosted to 600 mA for example?

cosco, AFAIK what you said is correct. Mine is boosted to run the lux at 667 mA and for intermittent up to 5 min should be ok. try it for your self. Also, don't feel bad on not changing the lux to Lux3 because you will want to run the lux only up to 1 amp in the arc head (minimum heatsink available) and at <700, lux 1 should be about equal to lux 3. Believe me, you would not notice the different between lux 3 and lux 1 at lower level. Well, unless you compare them side by side, you won't /ubbthreads/images/graemlins/tongue.gif

I am going to switch on my soldering station. /ubbthreads/images/graemlins/smile.gif

OK, it was real pain to solder the Dat2Zip's tiny 0,15R resistor. But I have not lost any. /ubbthreads/images/graemlins/smile.gif
See the mess /ubbthreads/images/graemlins/grin.gif picture
Next step is the McFlod reflector. Just when my eyes get back to normal /ubbthreads/images/graemlins/smile.gif

So, here's my problem. In showing off my noobiness while building my first sandwich, I:
- epoxied the lux onto an emmitter board,
- messed up the soldering job badly, which led to:
- smoking the MM board (a short, duh) /ubbthreads/images/graemlins/ohgeez.gif /ubbthreads/images/graemlins/banghead.gif

Anyhoo, since the lux did not die, I would like to use it in another sammie I want to build. Other than the way suggested here, has anyone successfully removed an epoxied lux? The solder job is so bad I don't think the emmitter board can be salvaged. Any ideas?

I was surprised seeing my old thread resurrected. /ubbthreads/images/graemlins/smile.gif

I think you can do the same as when removing the emitter from star. Use small sharp file to make deep straight scratch on the other side of the emitter board and bent it then by two pliers along the scratch. The emitter *should* pop off.

Somebody correct me if I am wrong.

Thanks for your suggestion, cosco.

I was afraid prying it with a screw driver, pliers, or heat may cause more damage because of the more direct physical manipulation. Filing the board is still physical manipulation, but of a more indirect nature. I think filing the board *might* be the safest way to go /ubbthreads/images/graemlins/smile.gif - famous last words... I'll definitely post here once I try one of your suggestions to let people know how it went.

Funny how one thinks very differently at 2 am...

I could not find my file, so I grabbed the lux base (the black thingy) with a pair of pliers, and the edges of the emmiter board with another. I twisted the board and the emmiter in opposite directions (slowly!) and the Lux came out easy!! /ubbthreads/images/graemlins/naughty.gif I probably went less than 1/4 turn.

The artic epoxy I used made a layer of about 0.5mm thick. Maybe this is why prying the lux off the board was so easy (and it's still working! /ubbthreads/images/graemlins/clap.gif). Maybe other people use more epoxy? I'm not sure, it seemed like my lux was seated at the same height than the emmiter on my BB.

We'll have to wait until somebody else tries the filing trick... How does dat2zip's emmiter board compare to the base of a LS in terms of size and thickness?

Greenled,

The idea with thermal epoxies is to get the layer as thin as possible. This is because the best thermal epoxies/compounds have thermal conductivities that are a small fraction of that for metals. 0.5mm/~.020" is about 40 times what you should have! Press down on that LS the next time you glue one. /ubbthreads/images/graemlins/smile.gif

Larry

greenled,

you are a killer! /ubbthreads/images/graemlins/smile.gif

I would not dare to do what you did. I screwed up one nice luxeon when prying from star with some blade. The black plastic part went off while the slug was still siting at the heatsink. Then I made a search and found the file/bending trick here in the forum. I wish I knew it before. /ubbthreads/images/graemlins/frown.gif

I press down and move it back and forth when epoxing my emitters. You can feel it sink down and settle, and not move so easy then. Sometimes you can even feel the metal to metal scratching.

Killer, moi?? /ubbthreads/images/graemlins/grinser2.gif
hmmm... Maybe I should change my nick to "LED_killer"? Or maybe, "can't build sammie but insists on fryin' components while tryin'" would suit me better. /ubbthreads/images/graemlins/crackup.gif

I guess I got lucky. You should see what the emmiter board looks like! /ubbthreads/images/graemlins/jpshakehead.gif If anybody asks how many mistakes one can make while building a sammie, I'll be happy to share my list. /ubbthreads/images/graemlins/crazy.gif

They say "practice makes perfect". I dunno about perfect, but using flux **really** helps in building sammies! The Lux I extracted from the sammie I smoked is now working on a MMlite I built last night! /ubbthreads/images/graemlins/clap.gif-for me! No more "LED killer" nick, I'm now "resurrects thought-to-be-smoked-luxes and puts in new sammie". Oh, I used the technique Isaac suggested to get a *thin* layer of epoxy.

I'm already thinking about my next sammie combination. This is addictive... /ubbthreads/images/graemlins/blush.gif (welcome to CPF?!) /ubbthreads/images/graemlins/grin.gif