LED strand only works with another strand plugged into the female end

[ChrismasJay]

I was trying to diagnose why my icicle lights were not working. When plugged into a normal outlet, the first 3 bulbs were very dim almost unnoticeable . To test if current was getting all the way to the end I plugged in a spare strand to the female end of the icicle strand. The icicle strand lit up beautifully but the 2nd strand did not at all. I took apart the female end and didnt see anything wrong. What could cause this?

 

[kellys_eye]

The whole strand is made up of a load of smaller sections wired in series so that when one 'bulb' goes out it doesn't stop the whole lot going out.

There are some good Youtube videos on testing christmas light strings to localise the faulty 'bulb' - you could try viewing a couple? DESCRIBING the method isn't that easy!

But since they are more expensive to repair than they are to purchase (especially when you factor in the problems with fault location and spares availability) they are not usually worth fixing.

 

[Harald Kapp]

they are not usually worth fixing.

Not from a monetary point of view but it gives you quite some satisfaction to save a bit of mostly working electronics and plastic from the junk.