I have these Christmas lights;



The first half of the strand lights up just fine. The second half of the strand is out.

My first thought was the fuse. There are two in the plug. Not sure if they both work, or just one works and the other is the spare, so I just went ahead and replaced them both. Same result, half the strand lit, the other not.

I assumed technology had progressed past the point of one bulb going out, the rest down the line going out, but I went to the first little LED bulb that was out. I pulled it out, and to my surprise, the rest of the strand went out. Now the entire strand was out. I installed a new bulb, half the strand lit back up, the other half did not. So at this point, I was back to where I started.

Since I replaced the fuses, and the first bulb that was out, am I overlooking something?

Figured I would ask before I toss a $20 strand of lights.

Could be a broken wire, you can take a new good bulb and use it to test each bulb in the section that's out, just replace it into one bulb at a time.

If you’ve verified both fuses are good, the culprit is either a damaged wire (possibly invisible) or a bad led or bulb connection. Get a verified working bulb and get to work checking them individually the old fashioned way. If the half is still out, then it’s a break in current flow somewhere. The local recycling center wire bin is usually loaded with led strings- more so than incandescent- I suspect a lot of folks just dump them and buy new strings.

quote:

Originally posted by holdem:
I assumed technology had progressed past the point of one bulb going out, the rest down the line going out, ...

Kind of. They've added a small component to the lamps that takes over and allows the rest of the string to work if an LED goes out.

Now the problem is crap leads on the lamps and and contacts in the sockets. They break or corrode, then even the built-in "fail-safe" can't work.

quote:

Originally posted by holdem:
Figured I would ask before I toss a $20 strand of lights.

Yeah, Homey ain't playin' that game anymore.

Every frackin' fall it'd be the same thing: Half a string would fail. So I'd painstakingly hunt-down the faulty socket connection and replace the bulb or, if I didn't have a replacement and there was enough lead to do it, solder-on replacement wire.

If that didn't work I'd replace the string.

This year it happened again. My wife had already bought a $15 replacement string. When one of last season's strings malfed I said "screw this for a game of soldiers," told her to return the new string, and didn't bother with the small tree I was going to do.

I bet China makes a ton of money off U.S. consumers replacing LED strings at $15-$20 a pop every fracking Christmas season

I would defer to an actual electrician on this, but I believe that not all the LED bulbs in these strings are equal. Some are just resistive loads with no bypass, others (the "key" bulbs") have a bypass resistor wired in parallel with the LED that allows current to pass when the LED fails. This feature my be built into the socket in some strings (a "key socket"). In either case, if the key fails, the string fails, but any other component only affects its particular location.

there is a pistol shaped test device to find root cause. i bought one at a thrift store. finds all sorts of issues.

https://www.walmart.com/ip/Gar...ight-Tester/22071313

But that test/repair device is only for incandescent lights
I got all my incandescents working using one this year, but I keep telling the wife I’m sick of all this cheaply made China crap

Here’s a pro-tip, after Christmas this year buy lights marked down 80% for next year, get a few extras.

Yes, cheap Chinese crap, but when you have problems, throw those lights away, start new.

OP here.

I wish lights would be marked down 80%. I went into Lowes on Monday, the Christmas stuff was pretty much gone.

I think I'll just toss this strand. Since the whole strand is 100 bulbs, and half the strand is out, no way I am going from bulb to bulb trying each one.

quote:

I assumed technology had progressed past the point of one bulb going out, the rest down the line going out, but I went to the first little LED bulb that was out. I pulled it out, and to my surprise, the rest of the strand went out. Now the entire strand was out. I installed a new bulb, half the strand lit back up, the other half did not.

Huh...
I'm still using the old C-9 set I bought in the '80s. I have a single socket that's out, but the rest of the strand still works.

Youtube vid showing diagnostic steps

Find where the path is broken, then diagnose the problem (either bulb, wire or connection).

The reason that 1/2 work is that there are 2 voltage paths, 1 gets broken & some can still work. It doesn't pinpoint the trouble spot, but it cuts the task in half. A non-contact voltage sensor will find the break & it's likely either in that socket, or the one previous.

I have several net lights that only partly light up. I just overlay them so that the parts that work make a uniform appearance at night. Looks messy in the daytime, but I don't care.

I have bought a bunch or new nets to replace the old ones that crap out, but so far have made do with the old ones.

I light up a lot at Christmas, and am in the process now (takes about a week with help from my Handyman). This is what it looked like last year:
DEC_4959.jpg by David Casteel, on Flickr
DEC_4955.jpg by David Casteel, on Flickr
DEC_4939.jpg by David Casteel, on Flickr

flashguy