LED Christmas lights gone dim

[KMoffett]

We have three strings of LED Christmas lights in series around our porch. Last night, my wife noticed that the middle string in the series was out. The two strings on the each end were fine. My grand daughter said "granpa, they're not out, just dim". I brought them in, and she was right. You can hardly see the light in the bulbs. All LEDs are lit, but very, very dim. I have no idea of how these are wired. I haven't done testing yet. Any suggestions?

Ken

 

[Audioguru]

I found a string of Christmas tree LED lights that were thrown away. Of course they did not work. I unscrewed the cover over an LED and the LED fell out. Its leads were not connected but were simply touching the wires of the string. Some of the LEDs have their leads and/or the string wires corroded where they touch together. Cheap junk.

 

[KTW]

Any suggestions?

Are they a different wattage?

 

[KMoffett]

All three strings are the same.

Ken

 

[(*steve*)]

Do they run from line voltage or something a lot lower? If they run from a high voltage it may be that it is actually just one string with a simple single point failure

 

[KMoffett]

110VAC. Two prong plug on one end and two prong socket on the other, so several strings can be run in series.

Ken

 

[shrtrnd]

My thinking is along *steve*'s .
You've got a single point failure in the dim string.
Sounds like a job for your granddaughter. I'd ask her to help you out by pulling and replacing each LED bulb
in the one string, to try to localize the socket (or bulb) that's the culprit.
Who knows, maybe she'll become an electrical engineer out of this.

 

[Audioguru]

The LED string that I found had corrosion in a few spots where the LED wires simply touched the string wires making a poor connection. At least one LED had one of its wires severely corroded and ready to fall off. That would cause dimming before complete failure.

 

[MWD]

Had the same issue. The culprit was the resistor at the end a string of LEDs. You can find it inside a little weatherproof cap along the string. A 50 cent fix at an electronics store. In my case it was a 1.8K Ohm 5% 2W resistor. Just replace with the leads bent upwards inside the holder.
-M

 

[Alimay]

Same issue here with a couple strands ! I Physically took every buld out and check 1 stard started working but the other is still dimmed...so frustrating the lights were bought less than a year ago just days before last christmas!

 

[Martaine2005]

Seems like this thread gets rejuvenated once a year each December!!.

If you took out each LED, the problem must be with the LED holder or wire going to it.
Double check the holders for corrosion. Use a tooth pick and a tiny piece of fine sandpaper to rub away any corrosion. Once all holders are clean bright metal, re-insert your LEDs with the same polarity they came out.
If you still have the same issue, plug them in and gently wiggle each wire at the holder end one by one until you reach the bad connection. The LEDs should either brighten or go off suggesting a loose or bad connection.

Martin