Cree Tri-XP-E2 Issue

[pipcorona]

I am working on a custom build and had some issues that made it seem like I had a wiring issue between my LED and my CEx. I have been doing a lot of testing of the wiring and something popped up that I wanted to check on. On my LED star that I got from TCSS, if I put one lead on the positive pad for the blue and one on the side of the star, it shows continuity. This is the only pad that does that. It seems to me that shouldn't be happening. Is that correct? I had noticed the problem and desoldered the wire, so it is just the tinned pad no wire on that pad right now. I checked all around the pad to make sure that there is no extra solder bridging any gaps or anything and can't find anything that looks out of place.

[atomsk]

its not impossible theres something wrong with the star, but its unlikely. ive had issues with pos-neg continuity b4, and it almost always is a tiny bit of solder bridging those pesky little half circle pads. its almost as if theyre meant to be bridged! but i dont think ive seen contuinuty with the heatsink b4. is it one of the custom machined 7/8 stars?

get a pic of it if you can. maybe someone can spot something

[pipcorona]

The issue isn't positive negative continuity. The positive for the blue doesn't have continuity to any negative except the one that it should. The issue is if I put the positive lead on the positive for the blue LED and the negative anywhere else else on the copper star itself (like on the side) I get continuity through the copper body of the star. I took a picture and have some arrows showing what I mean.

There is a full resolution version of the image here http://pipcorona.net/images/LED_Star_Full.jpg.

[darth_chasm]

its almost as if theyre meant to be bridged!

They are . They're there so you can easily commect the led's in series. That's what the "S" stands for. Learned that from reading about them on the Sinkpad website.

[atomsk]

yup! ive used em for CF builds, i just with they werent so close to the main pads.. cuz they can be annoying to unbridge.

i was really hoping something in that pic would be obvious, but i cant see anything unusual... pretty clean soldering on a sinkpad, especially considering its attached to the heatsink. u might need to ask tim about that

[pipcorona]

Thanks, I sent an email to Tim about the star. I noticed this when my CEx started acting up. I had to replace a resistor on that because of this so I'm really hoping once I get a star that isn't faulty my CEx is still working and didn't get too hot.

[Jay-gon Jinn]

Check the negative for the green...it looks like it may be stripped too long and is in contact with the star-pad's edge.

[pipcorona]

After emailing back and forth with Tim I desoldered the entire star and tested it again and got the same results. He said I must have burned through the tin layer of copper on one of the pads when I was soldering it.

[Strydur]

Thin layer.. and that is just my best guess. Shoot me another E-mail and we will get you a new one but I want that one back for testing.

[pipcorona]

Whoops...typo. I'll shoot you an email today.