Update on the Christmas lights....got the new resistors finally and had the chance today to solder them to the leds that had them. Took some time and some burnt fingers but both yard displays are back to full lighted mode! I had an issue with the newer one. Replaced all the burned out leds and once all the new resistor "loaded" leds were also plugged in, some were dim and one led wasn't lit. I pulled it and tested it, worked fine. Plugged back in and wouldn't light. Pulled again and checked the socket it fit into. It looked ok so pulled the wire out of it and tried the led directly...same problem. So somehow I noticed it was brigher before and thought... "is it backwards (positive side to negative)"??? YES! for some reason, this one led is installed opposite of the others... I don't know why but when I but it in backwards, it lit and all the others went to equal bright. This one it the first in the chain and doesn't have a resistor so I don't know the reason it works this way.

So I am down to one set of color changing leds that need to be fixed. This set just keeps popping the small 3amp fuses in the plug. When I test with the LED light keeper tool (uses a 9v battery), it doesn't pop the fuses and the leds function normally (at least the ones I saw, there are 36 and the line is 25' long). It has some sort of enclosed "cylinder" prior to the first led, which I assume there is some sort of resistor or diode that does something to the power for the leds. Here is a picture of it below and the set (it says 2018 which I believe is the year it was made). Is there a way to test the thing before I have to open it up (once it is identified)?