Defective lights

[Ralph Priest 18]

I have four strings of C6,70 ct. LEDs,purchased from CDI--all of which half of the string doesn't light---the first half and nearest the male plug. Strange,but true. Has anyone had any success repairing strings of non-replaceable bulbs?

[qberg 158]

I had a couple strands a few years back that I took an LED tester to.  Found the bad LED, soldered in a replacement from a donor strand (same LEDs and count) and then poof another would fail.  I finally gave up on those and tossed them.  I had already contacted the vendor and he sent me replacements under warranty.  If you don't have donor LEDS, the LED lightkeeper has "pods" to replace sockets and maintain the voltage/resistance.

https://www.1000bulbs.com/product/85857/CMS-LEDTESTPOD.html

I have had strands where the resistor inside the blob went bad,  soldered in a replacement and good as new. 

[Rotatorman 23]

As I prep for this years' display, discovered that a really nice blue LED snowflake I purchased a few years ago has LED's that are flickering, including a whole section that now has gone dark. So I contacted the manufacturer and was told the warranty was up.  I mentioned that Christmas lights are used for a short time each year, and based on what the snowflake cost, the manufacturer should take that into account. Because I'm new to this forum and don't know the rules, I don't want to bash the manufacturer, but will say I bought it at Target. If this forum allows, I will update with the manufacturer name so others can be aware.