Christmas lights - Page 1
Forum section: electronics / general

author: AndyC_772
author_rank: Super Contributor
timestamp: December 11, 2012, 09:38:29 pm
content: It's that time of the year again: put up the tree, fetch the lights from the attic, plug them in and... nothing. Once again I have to perform the annual ritual of pulling bulbs out of the string to find which ones have inexplicably died since last year. (I wonder, is it overkill to use a Fluke 289 to check for dead bulbs?)As always, they were working just fine when I put them away at the end of last year, but this evening I've found and replaced 5 bulbs out of a string of 80 - one fuse bulb and four others, all of which were the same colour. Orange bulbs, it seems, don't last in storage in the same way as red, blue and green.The bulbs are as cheap and nasty as they come, of course, but I must confess to having no idea what actually causes them to die between one year and the next - and certainly not what makes some colours worse than others. Anyone have any ideas?

author: PeterG
author_rank: Frequent Contributor
timestamp: December 11, 2012, 09:44:17 pm
content: I got a set of led xmas lights a few years ago. Still work and are a lot safer.Regards

author: G7PSK
author_rank: Super Contributor
timestamp: December 11, 2012, 10:24:43 pm
content: Its the mechanical shock from handling the lights that break the filaments, I have a 100 string of lights that has one red gone when I put them up today luckily the bulbs are of the type with the bypass resistor so easy to spot when they are blown. I have over the past couple of years slowly replaced the strings of lights with LED ones, I wait until after Christmas and buy them cheap and when too many bulbs are blown on the remaining light sets they will be replaced with LED's as well. A volt stick is quite useful for checking lights which don't have the bypass resistors.

author: bobhead
author_rank: Newbie
timestamp: December 13, 2012, 06:56:40 pm
content: I put up our 'pre-lit' tree last week and several strings were completely out. With a pre-lit tree, it's a little tougher to just replace the bad strings (unless you want to replace the whole tree). As G7PSK said, it may have been from rough handling or it may be that the bulbs are nearing the end of the useful life (the tree is several years old). When a whole string it out, it's mostly likely because one or more of the bypass shunts have failed. That's when you go on the bulb by bulb hunt looking for the blown bulb(s) with bad shunts.This year, I decided to try one of these:Light Keeper ProIt claimed to have a mode that would 'zap' a string of lights to activate any non-working shunts on blown bulbs. I figured for $17 and free 2-day shipping, it was worth a try.To make a long story short, I think it's the best money I've spent in a looong time. It works great. Remove any bulb from a non-working string (with power on). Plug the now empty socket into the tool. Snap the trigger (might take more than once) and the lights come on. Then just replace any blown bulbs in the string. In a short time, I had all the blown bulbs replaced (probably 50 or so).The tool claims to have all sorts of other functions for testing lights but the 'fix' feature is the only thing I've used. Once Christmas is over, I may do my own version of a 'teardown' to see how the zapper works.Bob

author: Nirios
author_rank: Regular Contributor
timestamp: December 13, 2012, 07:27:28 pm
content: Quote from: bobhead on December 13, 2012, 06:56:40 pmThanks for the link. I have a box full of light strings that have entire sections dead. It would be great if I could use them again without having to test each socket.