Emitter Swap Gone Wrong.

Marquis07

Newly Enlightened
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Aug 27, 2022
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B.C. Canada
I recently got a replacement TC15 with a cool white XHP35.2 in it, so I tried to swap out the emitter. I had done 2 sst20 swaps before, so I was feeling pretty confident. First off, I attemped to swap the emitter to this 5000K XHP35.2 I tried to heat the mcpcb with my solder gun on the bottom, but it was not working, so I used a torch instead. I did get the new emitter on, but I think I had too much or too little solder under it, and it was not aligned correctly. When I tried to reheat and align it, I bumped the emitter, and the dome fell off. :( All was not lost though. I also bought this 4000K XHP35.2 at the same time and I had an extra mcpcb from a broken light. I used a sheet of tinfoil covering a pan to heat up this second mcpcb and the emitter. All was going well, when suddenly black goo began coming out of the mcpcb, and the top started coming off. I rescued the second emitter, but it was too late. The base was seperating off of the top. In the aftermath, I realized that although I used a temperature gun to see how hot the tinfoil was, the pan was actually much hotter underneath. Instead of gently heating the mcpcb around 200F, I cooked it around 500-600F!



I now have a scorched but functional mcpcb and the original XHP35.2.



I still want to put a better emitter in the light, but for now, I want to get the original one back in. What should I do differently to have a better chance of success?

Before I order the emitters again, are these both fine for the light? 5000K XHP35.2 4000K XHP35.2 The second emitter is actually flat. How would this affect the light, and is it a bad choice because of this? The reflector is medium OP, although I have a smooth one I could use instead.

Following this thought^, Is there a better emitter that I should use instead of those? I would like it 4000-4500K and preferably hi cri.

I am also getting replacement 16mm mcpcbs. Would these XP16 v2 work, or would I need these XM16 v2?

I don't have solder paste, but I am planning to get some when I get my replacement emitter. Is it worth getting, or should I stick to just regular solder and flux?

When I swap the next emitters, I'm going to use a pan and solder paste. If there's something better I should use, please let me know.

Thanks,
Mark
 

gunga

Flashaholic
Joined
Nov 29, 2006
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8,083
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Vancouver, BC, Canada
I used regular solder for years. I finally switched to solder paste last year. I'll never go back. It's a lot cleaner and easier for me with paste.
 

desert.snake

Flashlight Enthusiast
Joined
May 8, 2017
Messages
2,142
Location
Eastern Europe
Any advice for next time?
Heating Plate for SMD Soldering. I killed too many diodes until I found out about the existence of these beautiful things

Some people make excellent soldering boards on their own


They are also sold on Amazon and other places. My friend jon_slider once showed his installation. But it makes sense, only there is to do it periodically, and not once every few years

Although you can continue to use a heat gun, you must first use a soldering iron to tin the contacts on the board, remove excess solder with a copper braid, then put the LED and heat the heat gun from below until it melts. I adjusted the position of the LED with a small wooden stick. If the amount of solder is correct, then the diode usually sits flat without any problems from 1 pass. But of course a soldering plate with temperature control is an order of magnitude better
 

louie

Flashlight Enthusiast
Joined
Aug 31, 2002
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1,114
Location
Seattle
I described my clothing iron and wire solder method in this thread:


I am a cheap SOB, and didn't figure I would do enough work to justify buying a reflow hotplate or even solder paste (which expires rather quickly).
 

Marquis07

Newly Enlightened
Joined
Aug 27, 2022
Messages
86
Location
B.C. Canada
Wow, thanks guys! I never thought about using an iron, that seems like a much better idea than a torch or heat gun.
 
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