Problems with U3 SSC

I recently received some U3 binned SSC LEDS from one of our dealers and after installing 2 of them in a couple of lights I'm having some issues. One of them replaced a SSC in one of my Novatacs. Has most of us know Novatac heatsinks come anodized from the factory to isolate the slug. I used Artic Alumina Ceramique has an insulator and reinstalled the spacer that was under the previous LED. Everything went smooth , and the light worked fine went put back together until I put the reflector/o-ring/glass/bezel combo in and screwed the whole ting down. Then the LED shut-off.

I disassembled the whole enchilada and the LED fires up again. At this time I was worried that the reflector may be contacting the leads but upon inspection the reflector sits on the casing of the SSC and when it makes pressure from tightening the bezel the LED then proceeds to shut-off again.
I tried the another of the 3 U3 I got thinking this one might be defective and got the same behavior.
Tried installing one on an Energizer one 1 watt, the same thing.
So my question is has anyone who has used this U3 before has experienced this? Or Im I doing something wrong? This is just a simple U bin to U3 bin swap, and I have done many of them before, so any help would be appreciated.:sigh:

Have not used any U3's but it seems like a simple fix would be to use a thin teflon spacer with a cut-out for the emitter dome stuck on top of the emitter. Or, even a piece of electrical tape with a cutout the same size as the reflector opening stuck to the underside of the reflector.

John F

My guesses are 1) the reflector is shorting out on your LED terminals, or 2) the reflector pushes the SSC P4 down so that the terminals contact something else that shorts it out. Since you say that the heat sink is anodized, it seems unlikely that the Seoul slug is shorting out.

For #1, even if the reflector contacts the LED's case, if your solder job is not tidy enough, the solder blobs can be above the top face of the case.

Check your soldering job. Try some Kapton tape under the reflector as an expedient.

For #2, you'd think that even after releasing the pressure from the reflector that the short would still exist. But perhaps there is movement of the LED when you disassemble the head again and that clears the short.

Ceramique is a thermal compound, not a thermal epoxy. Try some thermal epoxy to fix the LED in place.

I will post pictures of the assembly when I gét a chance... I always used the epoxy , but decided to go with Ceramique since its removable and the Novatac heatsink is anodized, thanks for the suggestions guys I apreciate it.

don't forget some beamshots too