DIY LED Troubleshooting?

[Reefmedic79]

Got my LED's all wired up and strung together, and only can get a third of them to fire up.

I think I narrowed down the problem to my soldering. It was pretty messy in the begining, but got better toward the end. The thing is I can't tell what may be a problem with it.

Unfortunately I don't have a way to post pictures of my current deal.

Was wondering what I should be looking for?
Is the star the diode is mounted to electrically conductive? I thnk some of my solder may be contacting the base, but not the heatsink.
Can too much solder be a problem?

Would it be better just to remove the solder and start from scratch since.

 

[redtop03]

I would probable start over but first go over the entire set with a magnifying glass before undoing anything,and double check all your solder joints and wiring,you may just have a loose wire..HTH

 

[Reefmedic79]

I would probable start over but first go over the entire set with a magnifying glass before undoing anything,and double check all your solder joints and wiring,you may just have a loose wire..HTH

Did that, could it be possible to have an incomplete connection, yet still have feel like the soldering is solid?

 

[redtop03]

it is possible.....

it is also possible that 1 of your LEDs is faulty causing your problem,test across each LED and each wire for continuity with an ohm meter,it should read like a short,if there is a loose connection,it should show up somewhere and narrow down your search....

if you don't find an issue there,test between the heatsink and the LEDs,it shouldn't read anything there,if it does,you have a short somewhere and may require a complete redo...hope you find it

 

[Reefmedic79]

Is an Ohm meter and Multimeter the same thing or capable of the same thing? Would a continuity tester (saw one at Wal-Mart) do the job?

All the LED's still work per the LED tester that I got from RapidLED to test them before they were tinned.

 

[bhazard451]

Is an Ohm meter and Multimeter the same thing or capable of the same thing? Would a continuity tester (saw one at Wal-Mart) do the job?

All the LED's still work per the LED tester that I got from RapidLED to test them before they were tinned.

If only a few light up on the same string, there is most likely a short somewhere. Check to make sure bare wire is not touching a star, screw, or the heatsink. Re-solder any connections that look like they might be.

 

[nemosworld]

check this over twice:
+-+-+-
make sure you did not do
+-+-- or +-++ somewhere
it happens to the best of us.

 

[fatoldsun]

Is an Ohm meter and Multimeter the same thing or capable of the same thing? Would a continuity tester (saw one at Wal-Mart) do the job?

All the LED's still work per the LED tester that I got from RapidLED to test them before they were tinned.

Yes, ohm/continuity is a setting on your multi tester dial.

 

[Reefmedic79]

No screws touching, and I have them in the right order. There are a couple spots where the solder may be touching the base of the star, but not the heatsink.

I saw this stuff at radio shack called a solder wick, is this what I use to get the solder off star? I can't seem to remove all the solder from the LEDs that are messy.

BTW, none of the diodes light up in the strings in question.



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[Reefmedic79]

it is possible.....

it is also possible that 1 of your LEDs is faulty causing your problem,test across each LED and each wire for continuity with an ohm meter,it should read like a short,if there is a loose connection,it should show up somewhere and narrow down your search....

Got a new multimeter and some desoldering braid today so I can get this thing fixed.

What setting on my multimeter should I be using when testing the continuity?
What reading should I get when testing across the wires?
Will the multimeter say short or is there a reading that would indicate a short?

 

[Hurdicuss]

Tagging along as I am currently having the SAME problem with my build. I am at my wits end with this thing, and I cannot seem to find the issue either. I had my cousin with electrical background trouble shoot it with me and my issues didn't make any sense to him either...

Not to hijack your thread, but in an effort for us to both solve our issues if I may add: I am experiencing the same issues as noted above, but in addition when applying power to my (2) strings nothing happens - but when i touch the heatsink some of the LED's very dimly light up. I have checked both strings for sloppy solders (though not with a magnifying glass yet) and even replaced some of the wires that I wasn't happy with to no avail. Performed a continuity test throughout the string (heat sink vs individual LEDs) and nothing. But I DO have continuity between some LEDs and the screw holding the led to the heat sink. I have since added nylon washers but still having this issue. One question I have is since the LEDs are wired in series, when there is continuity at one point in the string - will continuity register at every point within that string?

Like I said, at my wit's end with what my own knowledge is capable of but I hope you get your problem solved as well. Hopefully help arrives soon!

 

[Reefmedic79]

First of all, I'd like to thank everyone for thier time in helping me out.

Ok found another thread that explained how to do a short and continuity test. And everything passed, no shorts and everything lights up.

I then cleaned up some solder connections that where a little messy anyway and retested without any changes.

In my frustration I stepped away, took a breather and begin to think of what the issues was.

My set-up includes 3 6x6 heatsinks with 12 LED's, 4 of each color, and I got to thinking if there was some way I could hook up only 4 LEDs at a time, then maybe I can narrow down the faulty group (of 4) LEDs that is causing my issue.

Low and behold I did have a way; turns out I purchased the 4 moonlight kit from RapidLED as well and I had a small driver that ran at 350mA and was made for 4 LED's so I hooked them 4 at a time and everything worked, ALL LEDs light at least 4 at a time, so at the very least my soldering and wiring between the LEDs is ruled out as being the problem.

So my issue must be in how I'm wiring the driver and dimmer to the strings. Because I'm kinda just hand twisting some of the wires since this is temporary until I mount them in my hood could this be the cause if my intermitent issues?

 

[redtop03]

First of all, I'd like to thank everyone for thier time in helping me out.

Ok found another thread that explained how to do a short and continuity test. And everything passed, no shorts and everything lights up.

I then cleaned up some solder connections that where a little messy anyway and retested without any changes.

In my frustration I stepped away, took a breather and begin to think of what the issues was.

My set-up includes 3 6x6 heatsinks with 12 LED's, 4 of each color, and I got to thinking if there was some way I could hook up only 4 LEDs at a time, then maybe I can narrow down the faulty group (of 4) LEDs that is causing my issue.

Low and behold I did have a way; turns out I purchased the 4 moonlight kit from RapidLED as well and I had a small driver that ran at 350mA and was made for 4 LED's so I hooked them 4 at a time and everything worked, ALL LEDs light at least 4 at a time, so at the very least my soldering and wiring between the LEDs is ruled out as being the problem.

So my issue must be in how I'm wiring the driver and dimmer to the strings. Because I'm kinda just hand twisting some of the wires since this is temporary until I mount them in my hood could this be the cause if my intermitent issues?

I would think that a temporary twist to the wiring would be fine for testing and it should work....

can you post some close up pics,maybe we might see something that you're missing...I think you're getting close to solving your issue

 

[redtop03]

One question I have is since the LEDs are wired in series, when there is continuity at one point in the string - will continuity register at every point within that string?

yes....sound like to me that 1 of your screws is contacting 1 of the terminals on the star and shorting it to the heatsink...

can you remove 1 star at a time and test for a short ?

that way,you might narrow down the search to just 1 star and figure out how to insulate the connection from the heatsink

 

[Reefmedic79]

I would think that a temporary twist to the wiring would be fine for testing and it should work....

can you post some close up pics,maybe we might see something that you're missing...I think you're getting close to solving your issue

Will do, although it may be a couple days. If they are lighting with the mini driver, am I correct that it rules out the wiring of the strings themself, and should be just my wiring between the driver and the dimmer controller.

 

[redtop03]

Will do, although it may be a couple days. If they are lighting with the mini driver, am I correct that it rules out the wiring of the strings themself, and should be just my wiring between the driver and the dimmer controller.

yes,the wiring of each 4 LED set is fine,but when you're connecting all 12,something is messing you up there I believe

 

[Reefmedic79]

Well I got it all up and running, turns out that prior to mounting them I wasn't getting a good connection while I was testing them as a whole.

Here is a link of the build if anyone is interested:
http://reefcentral.com/forums/showthread.php?t=2205025

I'd like to thank everyone who helped me out.