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LED hookup

I just finished a couple of Cigar Box amps. Everything went well until I soldered the LED leads. I bought 2 prewired kits from Gitty. I checked the the leads with an ohm meter and had good continuity from the circuit board to the ends of the lead. Neither one of the LED's lit up when I turned on the switch. The amps both work well although not to loud. I can't figure out why the LED's don't lite. Take a look at the picks. Any help would be great

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Permalink Reply by The Capo Kid on October 9, 2013 at 10:01am

I may be wrong but I seem to remember when building shifts lights for my track car the LED has one leg longer than the other so maybe if you change the wiring round , does it tell you which way round the wire the LED ?

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Permalink Reply by Marcus P. Clarke on October 9, 2013 at 10:15am

both leads to the LED was the same but I did change them around and when I put together the 1st amp and the LED didn't work I used the one from the other kit and it didn't work either. Whats the chances that I got 2 bad LED lights. I checked the connections to the amp circuit board and the leads are in the right place according to the diagram supplied with the kit. I used one of these kits about a year ago without any trouble.

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Permalink Reply by The Capo Kid on October 9, 2013 at 10:49am

Strange that they sent the LED with equal legs , as how do you know which way to hook them up ? they should as I said have one leg longer which is the live and the shorter one the neg .

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Permalink Reply by jawbone on October 9, 2013 at 10:58am

I think there should be a notch on the base of the LED and that will be a reference point. But that aside - if they don't work the way you have it - the other choice is - try the other way.
I feel your pain - those LED's drove me crazy, as well.
Do you need to pair a resistor with it to work properly??

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Permalink Reply by Marcus P. Clarke on October 9, 2013 at 12:03pm

I went out and bought some new LED's from radio shack, they were clearly marked. I just finished hooking them up and they are working just fine. I must have had two faulty LED's from the kit. What are the chances of that, and I did try the other way.

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Permalink Reply by Old Fingers Green on October 9, 2013 at 12:06pm

I may be wrong but iirc If you hook up an LED the wrong way round the voltage kills it. They may have been fine at first but you may have unluckily wired both of them up the wrong way and blown them...

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Permalink Reply by Marcus P. Clarke on October 9, 2013 at 12:19pm

You may be right, I did power them up before I switched the leads. I have been known to make a few mistakes when building CBG's or Amps. I'm retired so I have plenty of time to fix them thanks to the folks on CBG nation.

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Permalink Reply by Dan on October 9, 2013 at 5:28pm

diodes only conduct one way. chances are you fried them if you hooked them up backwards. the notch should be the positive (+) side.

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Permalink Reply by Marcus P. Clarke on October 9, 2013 at 6:48pm

I didn't see a notch and it probably wouldn't have meant anything to me any way. Live and learn but thanks for the response. I'm all squared away now and the new LED's are working fine, and so are my CBG amps

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Permalink Reply by Old Fingers Green on October 10, 2013 at 5:21pm

Looking damn good too! Love those speaker covers!

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Permalink Reply by TruckDrivingFool on October 12, 2013 at 10:33am

Usually you need a resistor before the LED to drop the voltage, you may have over powered it and smoked it. You'll want to look at the specs for your LED but the ones I use get a 330Ohm resistor.

You can also tell the +ve lead by the short tang inside the globe.