For one who has the time but is low on funds ... how does one fix those strings of Christmas tree / colored lights that have the bulbs in series - presumably, if one bulb blows they all get knocked out? I have a multimeter and several non-working strings (so hopefully there are plenty of spare light bulbs).
Suggestions?
Thanks,
Henry
I have an electrical tester that I picked at the dollar store. If you hold it next to a plugged in extension cord, it will light up when held next to the hot / live wire, but won't light up when held next to the neutral / ground (even if there is nothing plugged into the extension cord). If you could find this tool, you could use it to trace the line, and find where it breaks, then replace that bulb, and continue till you get a working set.
I think the tester is called DEET or something.
If you just have a multimeter: set it to continuity test or resistance test. Remove a lightbulb and test the two contacts. If it beeps on continuity, or registers a resistance (near zero), then you know that bulb is good. Plug that bulb in and test the next one.
If all the bulbs work, then you might have screwed up sockets or wiring, which is a little harder to test. You remove a bulb, test continuity from both the prongs on the plug to the contacts in the socket, replace the bulb, and continue to the next socket till you find a problem.
It's actually pretty rare to have a "one bulb blows, the whole strand goes out" anymore. It _is_ still true in most sets though that if "one bulb is not fully seated the whole strand goes out". That being the case you usually only have to go through the set looking for the loose bulb(s) to get the strand to light up. Once the strand lights, the bulbs that are actually burned out are easy to spot.
Except for the very deluxe sets I only give them about 20 minutes worth of dicking with them. After that, they hit the trash and I buy another set. There just not worth more effort than that.
Now-a-days, the strings are so cheap. However, I still fix them, to a point. The big problem with using a multimeter is that the voltage (ohmmeter) is too low. Years ago, I built a box which we refer to as the Muppet Box, because it looks like something my kids saw on the Muppet Show (more on the box later). The lamps each have a shunt inside the bulb. The shunt doesn't make contact as there is some type of coating and the voltage across one lamp, in a working string, is only
1.5 to 3 volts. However, when one filament opens the entire 110 volts is now across the open circuit. The higher voltage breaks down the shunt coating and starts to conduct. If there are many open filaments in the string with all the shunts shorted, it will put too high voltage on the working lamps. I have seen a run away condition where the lamps start going one at a time and eventually they all die.The problem usually comes from 2 or more open filaments in the string. This probably happens from rough handling. There is not enough voltage to "share" between several shunts, so the string will not light. In the test box I have a 110 to 220 volt autotransformer. The output feed the light string through a series diode. There is a switch to switch between regular 110 volts and 220 volts through the diode. The string is plugged in at 110 volts and I momentarily throw the switch to the 220 volt side (half wave rectified). The higher peaks will, in many cases, break down the shunts and the string will light. I then switch back to the 110 volt side and change out the bulbs that don't work. The higher voltage will also arc through corrosion in the sockets in some cases. BTW, I also have other things (series resistors, etc.) in the box to allow manually probing the lights. There's also a GCFI to keep me alive in case I get careless.
All this said, there is (was?) a company that builds a high voltage pulser to break down the shunts. It was called Lightkeeper, however, I suspect they are out of bus> For one who has the time but is low on funds ... how does one fix those
Trip to the dollar store?
OK.
Make your own.
Hook up a single socket to a battery ......
In series, the voltage is divided amonst all the lights on the string so just calculate what you need, ands screw each one in one at a time.
Alternatively, find one STRING that works, unscrew one light and then test all your other lights on the working string.
Joel
True, of course if your wiring is screwed up your computer is not working so you can't read this either!
Not in series ,,,,,,,,, its an older, cheezier way of manufacturing Christmas lights .....
This could be like what is going on in Iraq .........
Joel
For reviews on some of these, check out:
If you can remove the bulbs, check them one at a time for continuity using the multimeter. A bad bulb will be open - infinite resistance. Replace the bad bulbs with good ones from the other strings and you should be in business.
If the bulbs are not removable, locate the bad ones by pushing a pin through the wire insulation before and after the suspect bulb. Now you can measure the bulb's continuity using your meter. When you remove the pins the insulation will close back up around the pinhole.
To replace a bad bulb, you'll have to cut out the old one, then splice the new (good) one to the resulting wire leads.
Note that the light string is UNPLUGGED for all of these tests. Apply power only after the repair is finished to see if you have more burned out bulbs.
One more thing - since you have extra bulbs, if you splice in a few extra bulbs into your series string, all of the bulbs will last longer. They'll dim slightly, but every 5% that you decrease their brightness will double their life.
Wiring in the string of lights, not the household wiring.
YUP guess so!
Ye-O-W-W-W-w-w-w-w-w-w-w-w-w!
100 volts!
Divide string in half by removing center bulb - check for continuity to one end of the cord. Repeat as necessary by dividing and checking each bad half of the remaining strings. 5 tests + confirmation of the bad bulb checks a string of 100. Dave
Eight, nine hours you should have it all checked.
>
Do they not make old style Christmas lights where there are sockets to screw in bulbs? You can still get bulbs for them.
I wouldn't know, since we're still using Christmas lights from at least forty years ago, though they did replace an older set that had the bulbs in series.
It sounds like the issue isn't that the bulbs are in series, that's merely a slow process to find the dead bulb, but that they are no longer socketed.
That would make them far more throwaway than the old style Christmas lights. On the other hand, from the flyers I see one can get them pretty cheap, so maybe nowadays people toss out the Christmas tree with the lights still on it.
On 11/28/2004 1:51 PM US(ET), Michael Black took fingers to keys, and typed the following:
Toss out the Christmas tree? I paid $60 for it a few years ago and it's still going strong. It's a pain to decorate and undecorate it every year, so I'm going to build a cantilevered closet addition in the corner of the LR where it is usually displayed, and when Christmas is done, just slide the decorated tree into the closet, close the door, and it's all ready for next year. I may put wheels on it, or some kind of extension track like on a slide away keyboard tray to make it even easier. :-)
Subject: Re: Fixing Christmas lights ... Reply-To: snipped-for-privacy@FreeNet.Carleton.CA (Michael Black) References:
Organizati> >
No, he's described a minimal search technique, though at the moment I can't recall what it's called.
He's dividing everyting in half, so each bulb does not have to be checked individually..
The first check defines which half of the string the problem bulb is in. The second defines which quarter of the string the problem bulb is in. And so on.
If the string has 100 bulbs, the first check immediately rules out fifty bulbs. The second check rules out 75 bulbs, the third check rules out about 87, the fourth check rules out 94.
Michael
I've found that by watching the sales, I can usually get 100 count strands of lights for around $2.50. I buy 2-4 boxes almost every year and don't bother messing more than a few minutes if a strand won't light. It's just not worth the hassle.
Melissa
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