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Thread: Havent Run into this before

  1. #1
    Flashaholic* Got Lumens?'s Avatar
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    Default Havent Run into this before

    What in the world . . .

    Enjoy










  2. #2

    Default Re: Havent Run into this before

    The LED desoldered itself?

  3. #3
    Flashaholic* Got Lumens?'s Avatar
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    Default Re: Havent Run into this before

    I think the bezel spacer may have twisted it off mistakenly when the owner went to change his battery.
    Those temperatures would have left behind more evidence?

  4. #4

    Default Re: Havent Run into this before

    Can you even change the battery by twisting off the bezel? Or was that a ďuser error?Ē Itís a little hard to tell by the photos, but that looks like a pretty clean break/disconnect. If the bezel twisted it off I would expect you would see little swirls in the solder?

  5. #5
    Flashaholic* Got Lumens?'s Avatar
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    Default Re: Havent Run into this before

    Quote Originally Posted by InvisibleFrodo View Post
    Can you even change the battery by twisting off the bezel? Or was that a ďuser error?Ē Itís a little hard to tell by the photos, but that looks like a pretty clean break/disconnect. If the bezel twisted it off I would expect you would see little swirls in the solder?
    There is a divot in the solder dead center. The plastic spacer is form fitted to the die of the LED and acted as a wrench when it had stuck to the reflector. The bezel is one piece, and the battery tube only opens from the tailcap. The tailcap was pretty darn tight and I needed a wrench to break it free. The owner is not a flashaholic, appreciates a good thrower light, and had no idea that the bezel might come off instead of the tailcap when going to change the battery. Proper care must be used to ensure the LED does not rotate with the bezel when taking such an animal apart for seasonal maintenance. I will add some locktite to the bezel threads for the owner once it's repaired.

  6. #6

    Default Re: Havent Run into this before

    Perfect opportunity for an emitter swap!! ;D

  7. #7
    Flashaholic* DIWdiver's Avatar
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    Default Re: Havent Run into this before

    Sure looks to me like the emitter was never soldered properly. It's amazing to me that this ever lit up.

    Ripping off a properly soldered emitter not only should have been extremely difficult (read: "not by removing the bezel"), but also should have caused massive damage, none of which is evident...

    I'd be mortified if this product ever left my shop.

  8. #8
    Flashaholic* Got Lumens?'s Avatar
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    Default Re: Havent Run into this before

    Ordered some tacky solder/flux

    Quote Originally Posted by DIWdiver View Post
    Sure looks to me like the emitter was never soldered properly. It's amazing to me that this ever lit up.
    Amazingly LED still operated after the LED dislodged and was not soldered.
    Last edited by Got Lumens?; 01-30-2019 at 10:12 AM.

  9. #9

    Default Re: Havent Run into this before

    I donít think Iíd want to use that same old LED... Being soldered multiple times canít be good for the LED or itís expected lifespan...

  10. #10
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    Default Re: Havent Run into this before

    Quote Originally Posted by InvisibleFrodo View Post
    I donít think Iíd want to use that same old LED... Being soldered multiple times canít be good for the LED or itís expected lifespan...
    Worst that an happen is I need to replace it if it fails . I will replace it with an XM-L2 if it fails. I don't own the light so the owner want's to reuse it first

  11. #11
    Flashaholic* DIWdiver's Avatar
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    Default Re: Havent Run into this before

    Wow, you're lucky the LED didn't fry. The solder connections are the only way to remove heat from the thing. While a little pressure from the reflector or something can provide an okay electrical connection, it provides a terrible thermal connection. The light must not be pushing the emitter anywhere close to its limits.

    If you bought some solder paste and plan to re-solder the connection, make sure to clean off the old solder as well as you can, and definitely clean any flux residue before applying the paste. Anything that looks like it could be removed should be removed.

    Isopropyl alcohol (IPA) cleans most fluxes pretty well. The higher the purity the faster it cleans and the faster it dries, but if you are only doing one it probably doesn't matter. Even 50% works, though 70% and often 90% are available at drug stores, even dollar stores.

    We use technical grade IPA at work (I think it's essentially 100%, but I never looked it up), but it's most readily available in 5 gallons and larger sizes. I use denatured alcohol at home because it's cheap, available by the quart or gallon at the home store, and I have it on hand for working with shellac. Plus, it works even better than technical IPA. Now that I'm thinking about it, I don't know why we don't use it at work. I should look into that. Acetone works even better, but due to its toxicity (low, but way higher than alcohol), I prefer to use it as little as possible.

  12. #12
    Flashaholic* Got Lumens?'s Avatar
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    Default Re: Havent Run into this before

    Quote Originally Posted by DIWdiver View Post
    Wow, you're lucky the LED didn't fry. The solder connections are the only way to remove heat from the thing. While a little pressure from the reflector or something can provide an okay electrical connection, it provides a terrible thermal connection. The light must not be pushing the emitter anywhere close to its limits.
    Yes I too was extremely surprised. It is not my light, so I didn't see what happened, but I believe the twisting happened when the light was off. When I first looked at it, the output was about 5%. I would guess the poor unsoldered connection limited the current. It only lit dimly when aligned correctly. Looking at the old solder, it looks like the LED had too much solder under it, like it had not been properly seated and pushing excess solder out of the way.

    What it a good recommendation for removing the old solder from the star and LED?
    I have a Weller soldering station, adjustable hot plate/pan, canned air, solder sucker, solder wick, and tech wipes.

  13. #13
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    Default Re: Havent Run into this before

    the soldering from the factory must have been very poor. The heat generated from the diode must have finished off whatever was there. I've had this happen to a few cheap flashlights I tested awhile back. Always stick to CREE bulbs

  14. #14
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    Default Re: Havent Run into this before

    Quote Originally Posted by Optiblue View Post
    the soldering from the factory must have been very poor. The heat generated from the diode must have finished off whatever was there. I've had this happen to a few cheap flashlights I tested awhile back. Always stick to CREE bulbs
    It is a Cree 20mm board and a Cree XM-L U2(?). I'm willing to guess that the poor connection to get the LED to light dimmly did not generate any heat. It was like 1 lumen .

    Update. Got the tacky flux. I thought this was a repair flux with added solder, nope, just flux that sticks better . I ordered some Kester EP256 that should do the trick. With all the supplies I'm buying, I may just order a star and LED. I want to see how this experiment works. upgrading will be extremely easy. The starboard is held in with two screws and thermal compound and very accessible.

  15. #15
    Flashaholic* Pellidon's Avatar
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    Default Re: Havent Run into this before

    Poor solder job (been there, done that). Or possibly they used lead free solder? It is brittle and harder to use compared to lead solder. I doubt the latter and expect the former.
    My doctor says I am a paranoid narcissist. I have the feeling I am plotting against myself.
    Rule #9: Always carry a knife. Rule #9a: Always carry a flashlight.

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