Despondent 1000 led Fairy Light string

Goliath

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My 31 volt ac 1000 led fairy light string was so despondent after the end of the festive season that it willfully threw itself into the path of the whipper-snipper. Valiant efforts on the part of the ever-alert operator restricted the damage to the last four or five leds, mangled beyond redemption. My old brain thought "Ah! just cut off the damaged section, look for a two wire section and cut it there!" This damn thing is three wires all the way back to the first led. The whole darn string ceased to light. Was my old brain befuddled with old DC thoughts? What's the fix do you think?

Also, I have several props that have a string of multi-colour leds, and a string of an equal number of white leds of the same brand/length. I generally pull these props apart every year, as stacking them assembled would probably result in wire damage. I have considered using a drill to attempt to twist the multi string and the white string together to make set up a little easier. Would this work or am I likely to just wind up murdering two led strings?
 

David_AVD

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I combined two 2-channel LED strings once to get a 4-channel string.

That was done with zip ties as I needed to keep them offset by one LED all the way.

I looked great at the time, but I honestly wouldn't put that much effort into 31V strings any more.
 

i13

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Am I correct in thinking that this is a multi-function 2 wire LED set and the referse polarity is the reason why you're referring to it as AC? If so then there should be places where it drops back to 2 wires but they'll be a long way apart and finding them won't help you. Light sets like this are usually wired as a big loop of parallel sections in series with each other. This is an example of a smaller set with similar wiring. https://auschristmaslighting.com/attachments/16216/
In your set, the sections will be wider (in the diagram) to accommodate the larger total number of LEDs. As you can see, a breakage near the end could cause the whole thing to fail.
 

Goliath

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I13, I call it ac 'cos the wee transformer outputs 31V ac. Two wires run from the transformer to the first led, then three all the way to the last.
 

David_AVD

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It does sound like it's a set that uses sections of parallel wired LEDs wired in series.

This type can't be easily shortened unlike the sets that use sections of series LEDs wired in parallel.

Does it have a link connector at the far end? That could be the reason for the 3rd wire.
 

David_AVD

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Oh, I just realised that the 3rd wire is probably one of the two coming from the MFC and is the return from the last parallel section of LEDs. The other wire from the MFC goes to the first LED section .
 
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