# Kroma - take that liquid weld!



## yclo (Mar 12, 2008)

Take a standard Surefire Kroma:





Take a McR20, USWOH SSC emitter, and a lot of swearing...





And you end up with a modded Kroma.





All the modes still function as before, but you get a lovely smooth beam with the McR20 and a lot more lumens from the SSC.

A few notes:

I used some heat to remove the mid section of the head. And in doing so, the black plastic spacer for the 3mm leds was slightly warped.

That darn plastic tab that provides the detents for the mode selection ring came off when I removed the ring, and I can't seem to get it to stay back on with the adhesives I have. Epoxy doesn't quite work on anodizing and plastic.

Oh the ring wasn't easy to take off either.

-YC


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## DaFABRICATA (Mar 12, 2008)

SWEET!!!:twothumbs

How the hell did you get the ring off?

I have been planning to do this same mod for a while now, but evry time I try to get my Kroma open I get discouraged.

That looks great! I would use my Kroma A LOT MORE if the main beam was nicer..

Good Job!:thumbsup:

Any pics of it apart?
I tried heat several time and still can't get it open...


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## Manzerick (Mar 12, 2008)

Great job!!! I can't wait to see where this goes!!


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## Norm (Mar 12, 2008)

Great job YC.
Norm


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## Gunner12 (Mar 12, 2008)

Nice mod, one of the very few who have done a Kroma mod.

From what I can remember, you might be the first on to post a Kroma Seoul mod here.


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## yclo (Apr 7, 2008)

Here is the plastic piece that provides the detents for Kroma's selection ring:


 

 



It came off because I twisted the selection ring past the point of resistance. Epoxy didn't seem to work well for gluing it back, but this seemed to do the trick.

This is the retaining ring that keeps the selection ring from coming off:


 

 



The selection ring for the U2 and Kroma are identical parts. The image with the arrows is a U2 head, and it does not use a plastic piece as the stop. In its place is a section of aluminium that has been machined into the head, it will not break off like the plastic piece on the Kroma.

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The following is a quick tutorial on how to remove the selection ring on a U2 or Kroma. DO NOT twist the Kroma's selection ring past the point where you feel resistance, the plastic tab will break off.

The tools you will need are:

A knife blade (the one with a broken tip is fine since it will most likely snap off when you apply pressure, alternatively anything that is really thin and stiff will do).

Several pieces of aluminium soft drink can sections cut to a small size.



 

 

To start off you want to insert the knife blade between the body and the selection ring, you want to insert the blade into the "break" of the retaining ring (shown with the green arrows). Once you do you will need to move around until the blade gets between the retaining ring and selection ring. Once you have that you will need the thin "shim" made from a soft drink can, insert it so that the retaining ring stays in the groove and you can carry on to the next step:



 

 

 

After the first shim, work your way around the ring(s) and insert the second shim. Repeat this step until you have 3~4 shims between the selection ring and body.



 

 



This will push the entire retaining ring into the groove and you should be able to pull off the ring towards the threads with your hands.

-YC


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## McGizmo (Apr 7, 2008)

Good job YC!

Now replace the Blue LED's with Nichia 310's and see what you get!


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## DaFABRICATA (Apr 7, 2008)

DAMN YOU!!!......I was just getting tired and ready for bed, but I think I heard my Kroma crying for a mod.


No really..._Thanks _for the how-to. I'm gonna work on opening mine now.


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## Supernam (Apr 7, 2008)

BRILLIANT! Amazing how you discovered how to do this. I wonder what would happen if you sent it back to SF for the detent repair.

SF serviceman: "WTH!... hey PK, come take a look at this. :twothumbs"


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## yclo (Apr 7, 2008)

McGizmo said:


> Good job YC!
> 
> Now replace the Blue LED's with Nichia 310's and see what you get!



Too late! Already put some UV leds in:





But I carry an independent flood anyway. :nana:

Maybe should've gotten a milspec, then I get 4 colour choices! But no more... I can't take Surefire's liquid weld anymore, it is too much for me.

On second thoughts, the red could be current driven. And if they are, a white replacement could be possible...... hmm..

DaFABRICATA - Just in case you hadn't realised, the Kroma head (like the U2 head) comes apart at 2 places):





1 will get you no where except to remove the lens, 2 is the one you want to get at. I had to use a _lot_ of heat, the Kroma was lucky but the U2 ended up having scratches on the head because the liquid weld didn't want to be beaten so easily.

And just to be clear, I did not come up with this method of ring extraction. It was posted on CPF a long time ago, the photos the person put up were not there anymore so I had to guess what he meant from the text.

-YC


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## DaFABRICATA (Apr 7, 2008)

I got it apart!!!

So what side is positive (+) on this K2? 

I take it you have to de-solder the K2 first before removing the heatsink from the board? Is there any thermale adhesive that needs to be scraped off before new emitter is in place? Anything else I NEED to know before I move forward? It looks like fiting my soldering iron in there is gonna be a tight fit!!

Where did you get the UV LEDs? I would love to do those in mine as well.

I'm going to add a link to this thread in my "Any Kroma Mods" thread.

Thanks again!


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## yclo (Apr 7, 2008)

Great!

I desoldered one side, then check the polarity of the led with a multimeter.

When I removed the original emitter, there was a lot of dried up thermal adhesive/compound around the heatsink. I just scratched all of that off with a small blade.

Actually, IIRC the SSC emitter is a hair wider than the lux and I might have had to dremel the heatsink a little for it to fit.

One thing I would probably recommend is putting some sort of shield between the soldering iron and the 3mm leds, I used a piece of cardboard. Lucky I did since the cardboard got charred in a few places when I replaced the emitter.

I got the UV leds from my good buddy koala.

-YC


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## DaFABRICATA (Apr 7, 2008)

Luckily I had an extra Mcr20 laying around and a new Seoul.

My kroma will be used more often now that the High is better. I would still like to replace some of the 3mm LED's down the road.

Thanks for the motivational help!!!:twothumbs

How did you get your reflector to stay in place? I had to flip the window and add an O-rind to the top to help hold mine in place:thinking:


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## yclo (Apr 7, 2008)

DaFABRICATA said:


> ......How did you get your reflector to stay in place? I had to flip the window and add an O-rind to the top to help hold mine in place:thinking:



I cheated.... I centered the reflector to the emitter and glued it to the heatsink.


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## DaFABRICATA (Apr 7, 2008)

Thats not cheating........whatever works!:shrug:


Also....the detent thingy broke off of mine as well. I just put it in place on the body while reassembling and it works fine. I can almost feel the detents better:duh2:


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## shinbone (Apr 7, 2008)

yclo said:


> And just to be clear, I did not come up with this method of ring extraction. It was posted on CPF a long time ago, the photos the person put up were not there anymore so I had to guess what he meant from the text.
> 
> -YC



Great work! If you are referring to my post in Defabricata's Kroma post you got the process and images just perfect. I hoped others would be able to decipher my text.


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## MorpheusT1 (Apr 8, 2008)

GREAT Step by Step guide!!!


Thanks Yclo :wave:
Benny


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## Grox (Apr 8, 2008)

It's very cool to see this mod in real life 

The beam is very nice with the reflector.

I was impressed at how professional the mod looked IRL and, having never seen a Kroma before, how small the Kroma is!


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## Icarus (Apr 12, 2009)

:wow: I didn't see this mod until now. Like Bennie :naughty: said... great step by step guide! :twothumbs


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## wquiles (Apr 12, 2009)

Very nice mod :wave:

Will


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## Alan B (Apr 12, 2009)

I wish this light was not so hard to take apart. Would love to have an upgraded one. Nice job!


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