3out of5 cobs won't turn on! Help!!!

[Mazer]

Hello ladies and gents. I completed my first two diy led. Each one with 5 Cree 2350 running at 500ma. I need low temperature. They are mounted on a heatsink 400x150x27mm with two (very noisy) fans each
The first light is running perfect. It is for veg with 2x4000k and 3x5000k no worries.
The second one is 5x3500k. Once all the wiring was done I tested it. It turned on ok. Then I went and did the final touches. When I tried it again, no light... Wiggles a few things around and then only two of the cobs turned on. WTF? I am no electrical engineer and solely rely on the tutorial you all graciously posted online and the research I have done.
Any idea what can be wrong? If it was a wiring problem the first two cobs should not turn on i suppose... Are they fried already???
HELP!!!!

 

[PSUAGRO.]

are you using cob holders or straight solder job? wired in series / parallel? and driver specs used?



some of the best DIY guys are on this forum, they will help you out

 

[Kul]

Likely that a cob has come loose from its holder. Happens all the time.

 

[VegasWinner]

make sure all of your holders a re secure and the wir4es are tight. should be a loose connection, as all was well at the start. peace

 

[BM9AGS]

Also blow it off with high pressure air if you were drilling any metal. Could have shavings somewhere.

 

[Mazer]

make sure all of your holders a re secure and the wir4es are tight. should be a loose connection, as all was well at the start. peace

But if it was a wiring plb would the first 2 cob turn on? they are mounted in series

 

[Mazer]

are you using cob holders or straight solder job? wired in series / parallel? and driver specs used?



some of the best DIY guys are on this forum, they will help you out

No cob holders unfortunately, straight solder job.
cobs are wired in series.
I am using a Mean Well ELG-150-C500B 500ma and 150W maxi (using about 92 out of the wall). running the cobs extremely low as I want minimum heat.

 

[Mazer]

Also blow it off with high pressure air if you were drilling any metal. Could have shavings somewhere.

I wish I could, I have no access to a compressor except my lungs...

 

[The Dawg]

Frist Of All Trying To Trouble Shoot You Problem Without Pics Is Just A Shot In The Dark. Sounds Like The Problem Lies In The Positive Wire On The 3rd Cob. You See If It Was A Negative Side Problem None Of The Cobs Would Lite. I Had The Same Thing Happen First 2 Cobs Lite up And 3 & 4 Wouldn't. Below Is A Pic Of What I Found.

 

[Mazer]

Frist Of All Trying To Trouble Shoot You Problem Without Pics Is Just A Shot In The Dark. Sounds Like The Problem Lies In The Positive Wire On The 3rd Cob. You See If It Was A Negative Side Problem None Of The Cobs Would Lite. I Had The Same Thing Happen First 2 Cobs Lite up And 3 & 4 Wouldn't. Below Is A Pic Of What I Found.

View attachment 3750773

Thanks for your input. And sorry for the lack of pictures. I finished up the build in a rush as I will be away from my workshop for the better part of this month.
My electricity knowledge is very limited and I do not understand how the first two cobs lit up if there is no "loop" in the circuit in case of a loose wore or something. Does not the current have to go back to the driver?

 

[sixstring2112]

Grounding through the frame might be enough to light up some of the cobs or you got sloppy with soldering and shorted those 2 bad cobs ?

 

[The Dawg]

When things are wired in series, things are wired one after another, such that electricity has to pass through one thing, then the next thing, then the next, and so on

.When things are wired in parallel, they are wired side by side, such that electricity passes through all of them at the same time, from one common point to another common point

You stated that you are running your cobs in a series and the 1st 2 in the series are working fine cause theirs no short in their wiring. The short start's with the 3rd cob so when you get back to your shop that's where I'd start looking 1st Peace And Opossum Grease

 

[Mazer]

When things are wired in series, things are wired one after another, such that electricity has to pass through one thing, then the next thing, then the next, and so on

.When things are wired in parallel, they are wired side by side, such that electricity passes through all of them at the same time, from one common point to another common point

You stated that you are running your cobs in a series and the 1st 2 in the series are working fine cause theirs no short in their wiring. The short start's with the 3rd cob so when you get back to your shop that's where I'd start looking 1st Peace And Opossum Grease

Yeah that much I understand.
Can not go to the shop as it is king brite...

 

[Mazer]

Grounding through the frame might be enough to light up some of the cobs or you got sloppy with soldering and shorted those 2 bad cobs ?

I don't know and I am soooo annoyed that I can not disassemble it before 4weeks... It's killing me