Christmas Lights question

[Shep]

So, my wife and I were watching tv last night, when a few lights from our Christmas tree got a little brighter than ususal. I walked over to examine what was going on when suddenly the whole strand went dark. I figured a few went out, but upon further examination I found that every light in the strand has gone out.

Does anyone know why this would happen? All the lights are 2.5 volts, and this is a pre-lit tree.

[phrog]

Fuse perhaps? My Christmas lights have a tiny little fuse on the electrical connection.
Richard

[Shep]

Have not checked the fuse yet, but if it blew first, the lights wouldn't have come on. Each individual light is now bad. I'll investigate more when I get home.

[crokett]

Personally unless you have an emotional attachment to those lights I would just go get new ones. They are cheap enough. If you do what to troubleshoot that strand, get one of those light testers.

[pelligrini]

From what you've said about the lights getting brighter and all the lamps being out it sounds like the transformer went bad and put too much voltage to 'em.

[LCHIEN]

the way these lights are made, they are in series, Lets say 40 3-volt bulbs each add up to 120V.

In the real old days they never made series connected lights because if one blew out (became open) then they would all go dark. A few years back they perfected cheap low voltage bulbs that would fail shorted so that the remainder of the bulbs would stay lit, i.e. the current would still flow.

However, there would now be 39 bulbs sharing 120V so each bulb would have say 3.1 volts on it. This is within the variability of the bulb and the power line. A couple more bulbs burn out then the voltage on each remaining bulb continues to go up (consistent with your noticing they got brighter)... eventually it goes up enough that the voltage is enough to shorten the bulbs life exponentially and then the whole string can theoretically go in short order, or the fuse blow out (They do have a fuse in the plug you know).

When individual bulbs go out you're supposed to replace them so the increasing voltage thing doesn't get out of hand. But the strings are cheap, just replace it.

[catta12]

Sounds like the fuse failed to function properly and let the whole strand become overloaded and popped them all. I vote for tossing them and getting a new strand. Cheaper than having to rebuild from fire.

[tung tied]

When you indicate that every bulb is bad, is that because you tested each of them in a properly working string? Or did the whole string just go out. If the latter, then. . .

Have you ever heard of the LightKeeper Pro? You could Google it. I think CVS or Kerr Drug (round these parts) may carry it. The LightKeeper Pro is a miracle tool (to me). It works by fixing the shunts on the burnt out bulbs that don't always short out correctly allowing the remainder of the string to stay lit. You remove any bulb, stick it in the LightKeeper, pull the trigger a few times and Wap-bop-a-lula! The string lights up (less the faulty bulbs) which are now easily identified and replaced.

[jbrain]

Originally Posted by tung tied

Have you ever heard of the LightKeeper Pro? You could Google it. I think CVS or Kerr Drug (round these parts) may carry it. The LightKeeper Pro is a miracle tool (to me). It works by fixing the shunts on the burnt out bulbs that don't always short out correctly allowing the remainder of the string to stay lit. You remove any bulb, stick it in the LightKeeper, pull the trigger a few times and Wap-bop-a-lula! The string lights up (less the faulty bulbs) which are now easily identified and replaced.

Great tool. Bought a few weeks ago. Seems too good to be real, but it works. It WILL same me some $$ and frustration in the years to come. I just used to keep buying more lights. At least now I have a fighting chance.

[crokett]

I have one that somebody gave me but it doesn't work all that well for me. am willing to concede user error but I still ended up buying a new string of lights last year.