It's that time of year again... Christmas tree lights - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: December 19, 2019, 02:59:53 pm
content: So... dusted off the old Christmas Tree lights (incandescent strings), tested them, put them on the tree and then 24hrs later a segment doesn't work... so...Although the incandescent technology won't be us beyond the last spare bulb (we have a few) it got me to wondering again how I could go about working out the broken bulb... it seems that the wiring goes from the 240V plug to a set of parallel strings and that a single failure in one of the strings leads to the string going out. I have read about gadgets that help diagnose but I don't know how they work.I was wondering... maybe I could unplug the set from the mains and inject a signal into both sides of the string... say square wave on one side and an exactly out of phase signal into the other side. Then I could measure the amplitude at the two pins of the light bulb which will give me two voltages for each of the phases... four measurements in total.Does that sound enough to identify which direction the fault lies? (I have to factor in the flow in the reverse direction around the correctly functioning strings)

author: rvalente
author_rank: Frequent Contributor
timestamp: December 19, 2019, 03:37:23 pm
content: Usually to fix the lights all you need is some patience, spare bulbs and a meter in continuity mode.I do not believe the segment is bigger them 15 lamps in series. So you could check eye naked for broken filaments.As for testing in a fancier way, maybe using a waveform gen and a probe, you could try to find the electric field in the string. Just a thought

author: richnormand
author_rank: Unknown
timestamp: December 20, 2019, 02:12:10 am
content: I use a AC voltage detector as sold in many home improvement stores. These are cheap and will beep when an outlet is live.Separate, by hand, the wires between the live and the neutral. Check to find out which is the live at the plug.Follow it to the first bulb, then keep separating the wires and tracing until the signal dies down. The open bulb will be close.This also works with LEDs as I found out this year (open blue LED in an old string).

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2019, 03:56:09 am
content: I use either a multimeter or I just get a known good bulb and swap it into one location at a time. Most of the time with the push-in miniature lamps it's not the bulb that has failed but one of the wire leads has broken or is bent around and not touching the contact. The type we've had here at least as far back as the early 70s has shunts in each lamp that prevent a burned out filament from opening the circuit.While I've been LED everywhere else for years I'm not fond of LED christmas lights. They flicker, most of them are dim, they all have exactly the same colors immediately identifiable as LED, there's just something I find icky about them. I'm using 1970s C9 lights on the outside of my house and my tree has a mix of C6 strings from the 40s-50s and some 90s C7 bubble lights, all of it incandescent.

author: GreyWoolfe
author_rank: Unknown
timestamp: December 20, 2019, 01:28:01 pm
content: Quote from: james_s on December 20, 2019, 03:56:09 amWe have just the opposite experience. We have gotten rid of all of the incandescent lights. We have lights on the tree that are very bright, garland hung around that are somewhat dim, which is perfect and some fairy lights on shelving units and all have a different shade of white. The outside icicle lights are also quite bright along with the lights on the outside tree. The LED lights on the reindeer are not as bright but still very noticeable from several houses away. None of us notice any flicker at all. I much prefer the LED lights. I do miss the bubble lights of the 60's on the tree that I grew up with, though.

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2019, 04:48:29 pm
content: My mom can't see the flicker either, just the other day I was over there and noticed that she had LED lights on the lower half and incandescent on the upper half of a tree outside her front door. She didn't notice they were different but I could see the flicker immediately and she was astonished when I used the slow-mo video feature on my phone to film the tree and playing back the flicker was extremely obvious. Some of the LED christmas lights are much more flickery than others but I've yet to find any that don't flicker.I think I mostly like the incandescent stuff just because it's vintage though and old stuff I remember from when I was a little kid is part of what makes christmas feel cozy.

author: ebastler
author_rank: Super Contributor
timestamp: December 20, 2019, 04:53:01 pm
content: Candles, anyone?We still have them on the tree in the living room. Accept no substitute!

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2019, 04:57:34 pm
content: Yikes, I'll use 70 year old strings of incandescent lamps with cloth covered wires but I'm not letting open flame anywhere near the tree. Evergreen trees are quite flammable and can go from a small flame to a huge fireball in a matter of seconds.

author: Zero999
author_rank: Super Contributor
timestamp: December 20, 2019, 07:08:00 pm
content: Quote from: james_s on December 20, 2019, 04:48:29 pmCheap LED lights do flicker. Get the type which are run from a proper DC switched mode power supply and they won't flicker, unless they're RGB with low frequency PWM. Avoid LEDs powered straight from the mains using a resistor/capacitive dropper and rectifier.Back in the 90s, I made some nice Christmas lights with just red LEDs, which looked much better than some of all blue ones which seem to be fashionable nowadays. I don't know what happened to them. I've toyed with the idea of making my own Christmas lights again, with a greater range of colours, but haven't bothered because it's cheap to buy them, although being able to choose different colours would be nice.

author: james_s
author_rank: Super Contributor
timestamp: December 20, 2019, 07:23:28 pm
content: I don't think I've ever seen any that had a proper SMPS. Here in 120V land miniature christmas lights are invariably series wired and directly mains powered. I was surprised when I initially started discussing this stuff with a British friend to discover that transformer powered miniature lights are common there. I suppose with the higher voltage drove things toward a different design and things just kind of stuck.I do think that eventually LED tech will get where it needs to be to make this sort of thing really good. Phosphor type LEDs in a rainbow of colors will allow a bit more variation in color output and better brightness matching from color to color. It would also be nice to see more true red LED decorative lights instead of the reddish-orange that is typically used.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: December 20, 2019, 09:44:52 pm
content: My father described Christmas lights as being at least two open circuits in series.@james_s : Over here in Brexitland, we kinda gave up on the trauma of 'Dad' fixing the xmas lights the old fashioned way. Now every tree and house is strung with LEDs. PSUs are tiny switch mode boxes, not those solid brick transformers that will break concrete, and toes, when dropped. Compared with incandescent lamps, LEDs are so cheap there is no incentive to treasure and maintain lamps from year to year. And certainly no need to hold a mix of replacement bulbs at the correct rating. Some local councils recycle defunked lights to keep copper and plastic out of landfill. Furiously cold white LED's are in vogue this year.btw, we have some very ancient festive lamps, made in China even back then! Sometimes we gently power these through a dimmer circuit. Pictured are 12 voltchinese lanternsfrom what we suspect is the mid 1930's. But if you guys have a more accurate date, then please do tell.Season'sGreetingsEEVBlog.

author: Zero999
author_rank: Super Contributor
timestamp: December 21, 2019, 09:50:57 am
content: Quote from: james_s on December 20, 2019, 07:23:28 pmebay seems to be full of 12V or 24V Christmas lights if you explicitly search for them.Colour has always been a problem. The old incandescent lamps have a low colour temperature, making blue and green dim and dies fade due to heat, so the colours wash out after awhile. It's true modern LEDs are often a bit blue or cold looking, even the mixed colours. My set which has red, yellow, green and blue use phosphor for red, yellow and possibly green, with blue only being plain LED, and the blue is a little brighter than it should be. It's still dimmer than the other colours, due to the poor sensitivity of the human eye, at that end of the spectrum.

author: Electro Detective
author_rank: Super Contributor
timestamp: December 21, 2019, 10:05:49 am
content: It's that time of year again... Christmas tree lights=fwiw they didn't have all this stuff back in Christ's day, did they even have readily available cheap MIC candles?so why do we 2000+ years later.. risk life, limb and or sanity to set up these circus sideshow displays?Where in the good book does it state or imply 'thou shalt without question expose wallet, and break ass to set up chrissie lights..and troubleshoot if necessary with whatever means at your disposal.Yoel Have A Nice Day..'

author: tooki
author_rank: Super Contributor
timestamp: December 21, 2019, 03:35:40 pm
content: Quote from: ebastler on December 20, 2019, 04:53:01 pmWe were absolutely shocked at our first Christmas in Switzerland (1992) when everyone put candles on their trees. In USA, where we moved from, that is absolutely unheard of in the modern era.Quote from: james_s on December 20, 2019, 04:57:34 pmFYI, to the other shocked Americans: 1. Aproperly hydratedChristmas tree will not go up in flames if a single candle flame licks a branch for a second. (Ideally you should cut a fresh edge onto the trunk so that it can absorb water better.) 2. One NEVER lights candles except when the tree will be actively supervised. So that means the tree is lit only a handful of times the whole season. 3. It’s nonetheless a wise precaution to keep a fire extinguisher at hand, just in case. Xmas tree fires do happen every year to people who have violated the prior requirements, especially the one about keeping the tree hydrated, since dry evergreen needles do indeed burn exceedingly fast.

author: madires
author_rank: Super Contributor
timestamp: December 21, 2019, 03:56:45 pm
content: I've upcycled some old "made in China" tree lights with small incandescent lamps which where popular about 15 or 20 years ago. The lamp's diameter is 5mm.This asks for LEDs and a capacitive dropper PSU. And because we like fancy stuff I bought color changing LEDs (the slow changing type) to replace the incandescents. Looks quite nice and the neighbor's LED lights are all single color.

author: German_EE
author_rank: Super Contributor
timestamp: December 21, 2019, 04:25:58 pm
content: Go Jewish, seven lights and we're donehttps://en.wikipedia.org/wiki/Menorah_%28Temple%29

author: Electro Detective
author_rank: Super Contributor
timestamp: December 21, 2019, 11:12:13 pm
content: Quote from: German_EE on December 21, 2019, 04:25:58 pmThat's a burglars 'Gold Christmas' depending on the neighborhoodand how many gates and cameras going or not..

author: james_s
author_rank: Super Contributor
timestamp: December 22, 2019, 03:43:28 am
content: The lights have always been my favorite part of Christmas. I'm not religious so I don't really care about that aspect of the holiday but the lights and decorations are a nice way to brighten up what is in this part of the world the most dark and gloomy time of the year.

author: Zero999
author_rank: Super Contributor
timestamp: December 22, 2019, 11:13:24 am
content: Quote from: tooki on December 21, 2019, 03:35:40 pmBetter still get a Christmas tree with proper roots. I use the same one every year. It goes in a shady spot in the garden, over the summer and is watered regularly, especially durinh in hot, dry weather.Having said that, I deem using candles to be too risky vs the benefit and prefer to use LED lights.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: December 22, 2019, 07:29:20 pm
content: Goodness me... a couple of days go by and I come back and find the thread has been lively!In the end I had to use a multi-meter and watch the ohms increase down the string... I have worked out it is a dodgy wire... just haven't worked out which one yet but with a bit of wangling the lights are currently lit.Will switch to LEDs next year.

author: james_s
author_rank: Super Contributor
timestamp: December 22, 2019, 07:36:48 pm
content: Another trick I have used since I was a kid is to take a known good bulb and swap it into the first socket, then take that bulb and swap it into the next and so on until you reach the end of the string. This of course only works if you have only one bad bulb and in a multicolor strand it will screw up the color ordering. You can also use a 9V battery to test each bulb individually.Switching to LED has some advantages but it won't get you completely away from troubleshooting. I've had a number of LED strings and eventually they all failed. Some of them had individual LEDs fail and eventually the whole string crapped out, others faded and looked yucky after just a couple years. Ultimately I was disappointed to find the LED strings didn't last as long as the incandescent strings they were meant to replace. This was several years ago so they may have improved by now but the drive to keep costs low leads to cutting corners by using cheap LEDs and cheap plastics that rapidly yellow in the sun.

author: ebastler
author_rank: Super Contributor
timestamp: December 22, 2019, 07:52:02 pm
content: Quote from: james_s on December 22, 2019, 07:36:48 pmAh, there's your problem! In this part of the world (Northern Germany), we don't do much "sun" at this time of year.

author: james_s
author_rank: Super Contributor
timestamp: December 22, 2019, 07:57:41 pm
content: We don't get a lot of sun in the winter but even on cloudy days there can be a lot of UV. It's also not uncommon to have cold, clear days where it's down around freezing or below but there is still strong sunlight during the day.

author: Zero999
author_rank: Super Contributor
timestamp: December 22, 2019, 08:03:49 pm
content: Quote from: james_s on December 22, 2019, 07:57:41 pmWhere do you live? Is it high up? Where I live the UV index never gets above 1 at Christmas time, even on clear days.

author: james_s
author_rank: Super Contributor
timestamp: December 22, 2019, 08:09:15 pm
content: Near Seattle WA.I've never actually paid attention to the UV index but I have certainly had plastics yellow in the winter.

author: Gyro
author_rank: Super Contributor
timestamp: December 22, 2019, 08:47:59 pm
content: Quote from: tooki on December 21, 2019, 03:35:40 pmThat used to be a totally anal form of torture in our household, before we finally gave up and went for an artificial one!First stand outside in the freezing cold with the tree balanced on the garden bench after dragging it off the car. Then saw a couple of inches off the bottom with a hand saw while SWMBO slowly poured freezing water over the saw, cut and fingers to avoid airlocks and wash away spilt blood. Then split the bottom of the trunk in at least three directions with a chisel and drill a few holes for good measure (while continuing the water torture) to maximise absorbing area. Then plunge into a bucket of water, (breaking the ice if necessary!) and leave outside for a week. Dry saw, drill bits, chisel etc and oil as necessary, sweep needles off car. Finally attend to chilblains!After week, bring inside, originally in the bucket (remove slugs), wedged with bricks and much swearing to get the trunk perfectly vertical, more latterly in a cast iron stand with water reservoir. Then cut the top off the optimistically chosen tree to make room for the fairy between the top and the ceiling. We never had needle drop though.The final change came when we found that one of the DIY stores had a realistic looking artificial one on offer, cheaper than we could buy a dying one. That was about 10 years ago. Filament bulbs which had lasted since we were married in 1984 and still working, finally replaced with LED a couple of years ago. Christmas issomuch easier these days.

author: ebastler
author_rank: Super Contributor
timestamp: December 22, 2019, 08:56:40 pm
content: Quote from: Gyro on December 22, 2019, 08:47:59 pmI recommend this inflatable tree with interior lights.

author: james_s
author_rank: Super Contributor
timestamp: December 22, 2019, 09:07:10 pm
content: Quote from: Gyro on December 22, 2019, 08:47:59 pmThat sounds drastically more involved than what I do. Unload the tree and lay it in the driveway, buzz an inch off the bottom with my cordless reciprocating saw, slap the base of my adjustable stand on and crank down the screws. Then carry it inside, set it up in the stand, adjust it to level and fill the stand with water. Cut the bundling net off and let it settle for a bit and then decorate. The actual setup takes about 20 minutes, most of the work is decorating it. Yeah an artificial tree would be marginally easier as I wouldn't have to drive anywhere to get it but the real ones make the house smell nice.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: December 22, 2019, 09:30:03 pm
content: Maybe Jehovah's Witnesses have the right idea? They do not celebrate xmas and easter as they believe these are pagan festivals and not true Christian events. So that's no lights, no trees, no cards, no wrapping paper, no waiting in line to meet some grumpy shopping mal Santa, no 'amusing' office Secret Santa gifts, no sexual harassment claims after the office party, no Rudolph jumpers or stupid Pixie hats, no festive shopping muzak, no keeping the receipts (shewillhate it), no under/over cooked Turkey, andabsolutelyno hoovering of random glitter particles off the furniture. Oh what joy to the world! Anyway, as a pagan I say to the EEVBlog community, happy Winter/Summer Solstice < depending on your hemisphere.

author: Gyro
author_rank: Super Contributor
timestamp: December 22, 2019, 09:52:31 pm
content: Quote from: james_s on December 22, 2019, 09:07:10 pmYeah, I did say I got pretty anal about it!I do agree about missing the smell though.P.S. Why, in all those years, did I never think of cutting the net offafterit was in the house?It always used to come off the week before, outside, to settle and collect crud!

author: Electro Detective
author_rank: Super Contributor
timestamp: December 23, 2019, 02:22:56 am
content: Yeah, great fun finding UV crumbled chrissie light gutter clips hiding in grasswith bare feet in summerA few years back I got lumped with boxes of these typical generic -origin of manufacture unknown and or unnamed- infernal lights,tangled and manged to hell, different strings and brands? to sort out =and if memory serves (one last time about this pet hate) I rigged up some shorting wire thingies to poke into random light sockets, even if the globes looked and tested ok,and after about ten or so pokes, I fixed the lot,but due to lack of replacement bulbs, sacrificed the last few in the end of the string/s, which got wrapped up and hidden away out of sight.I 'think' I had to terminate something/somewhere for the return path/s =fwiw there were a few loose and or crusty sockets to clean and 'tighten' as well as dud globesDoes this sound right? Pretty sure that's how it went down, I do remember wearing a magnifier with a torchThey were a hassle to separate before the troubleshootand even once they were working, they were still a PIT?to untangle and organize properly for mounting and packing laterI found that gently rolling the chain loosely in a box and labelling both ends goes a LONG way to keeping ones sanity..Yep, I hate em, there I said it.I don't mind the Christmas vibe, but not some of the unnecessary and 'irrelevant to the actual real occasion' BS that goes with it

author: xrunner
author_rank: Super Contributor
timestamp: December 23, 2019, 02:35:29 am
content: Quote from: Electro Detective on December 23, 2019, 02:22:56 amLOL that was a hoot reading, but dude get a laser Xmas display source, put in yard or wherever, shine on object, and relax.

author: Magicshark
author_rank: Newbie
timestamp: December 23, 2019, 04:10:42 am
content: If I were you, I'd better buy new ones. Once, I had my Lights broken, I'd tried to fix them, and nothing good came out.

author: tooki
author_rank: Super Contributor
timestamp: December 23, 2019, 08:43:02 am
content: Quote from: Zero999 on December 22, 2019, 11:13:24 amHere in Zurich, where most people live in apartments and have at most a balcony, but no garden, there is a service that lets you rent a potted Christmas tree, then just return it after New Years. It costs about the same as a cut tree, which I think is fair given the work to nurse the trees the rest of the year.

author: Electro Detective
author_rank: Super Contributor
timestamp: December 23, 2019, 09:53:47 am
content: Quote from: Magicshark on December 23, 2019, 04:10:42 amGreat advice to be sureUnfortunately stubborn'I got this..'suckers like meget 'good coming out of bad' from landfill worthy house igniting eye candy,so as not to spoil the festive vibe for young and older low on cash..Atheists, agnostics? scrooges, andFATSantaClutzhaters in general know how to save themselves a lot of drama and money,and enjoy theirHAPPYHOLIDAYS without having to think about calling the Fire Brigade/Department in that high risk 60 day period.FWIW Christmas with all the BS lashings, is still a better deal than WEDDINGS,when all the closet crazies expose their concealedMENTAL ISSUESAdd medication, alcohol, not so legal substance indulgence to that, plus the usual gossip stirring(the bride is bonking the best man and or vice versa)and even a well trained security team will choose to lose the pay and do a runner

author: james_s
author_rank: Super Contributor
timestamp: December 23, 2019, 07:10:11 pm
content: Call me weird but I find untangling and resurrecting christmas lights to be somewhat therapeutic, it's a bit like knitting I guess, something I can sit on the sofa and do while I watch TV. Always a nice feeling when a dead string springs back to life.