How to choose an appropriate LED

[olds...@tubes.com]

I have one of those costly animated outdoor Christmas displays with
white LED lights on it. A few of the LEDs are dead. There is no
manufacturer info available.

I know LEDs all have a different current draw. I am not sure how
critical it is, to choose a replacement bulb. Does it matter, or will
any white LED work, as long as it fits the socket?

These are sort of the domed type, but have flat tops. Nothing fancy, and
they dont have to look identical since they are inside of a coating.

My thought is to just buy a string of white xmas lights after the
holiday (on sale) and use them for replacement bulbs. But maybe I need
to know more about the current draw or something. I
ve never had to replace LED bulbs before. I replaced amny of the old
xmas light strings that has incandescent bulbs, and with them, you had
to match the number of bulbs to get the correct voltage.

[Jeff Liebermann]

Two days after I hung my string of Hanukah lights, the local squirrels
gave it a taste test resulting in about half the string going dark.
You might inspect your lights for similar damage. If so, splice or
solder the wires back together and it should work. Be sure to use
shrink tube or liquid electrical tape for insulation. My 25ft string
has about 6 breaks from similar squirrel damage from previous years.

If you plan to fix it, take the time to determine how it's wired. Some
possible schematics and wiring diagrams:
<https://www.google.com/search?q=led+christmas+light+wiring&tbm=isch>
Trace out your wiring and see what matches.

Try to fix just one section that's currently not lit. If you find it,
don't fix it immediately. Use a VOM or DVM to measure the current and
you have your answer. Some LED's have built in resistors or current
regulators like this:
<https://www.google.com/patents/US8007129>

You can determine which LED is blown in one segment, attach needles to
the VOM or DVM leads and probe across each LED by puncturing its
wires. If you see an unusually large voltage, the LED that you're
straddling is the culprit. Be careful as most light strings do not
have any isolation from the AC power line. Use a 117-117VAC isolation
transformer or be VERY careful when probing live power.



--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[whit3rd]

On Monday, December 25, 2017 at 12:35:44 PM UTC-8, olds...@tubes.com wrote:
> I have one of those costly animated outdoor Christmas displays with
> white LED lights on it. A few of the LEDs are dead. There is no
> manufacturer info available.
>
> I know LEDs all have a different current draw. I am not sure how
> critical it is, to choose a replacement bulb. Does it matter, or will
> any white LED work, as long as it fits the socket?

There's multiple shades of 'white' available; if you can't see
the replacements side-by-side, they won't be exact.

Generally available (new stock) LEDs in the same package are likely
(for heatsinking reasons) to be electrically compatible. And, cheaper
than a set, you can get bags of LEDs from a variety of suppliers,
like this: <https://www.ebay.com/itm/3mm-white-LED-light-100pcs-Light-Emitting-Diode/182490012569?epid=571206918>

but polarity, case size, color, are just as mysterious as the 'no manufacturer
info available' item you are thinking to rebuild.

[olds...@tubes.com]

On Mon, 25 Dec 2017 14:18:44 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

Thanks for the help. This is an outdoor display, but I use it indoors.
So no animals have chewed on the wires. I dont hasve whole sections out,
just two or three bulbs that dont light. I could just leave it alone,
but if it's series wired, I know it will eventually overload other
bulbs. (Yea, I need to get a better look at the way it's wired). Plus
this was a very costly and very pretty display, so I want to keep it in
tip-top shape. (Which is why I only use it indoors).

The reason I got this, was because it was a store display, and I got it
at a much reduced price. So, running it in the store for weeks probably
killed the weak LEDs. However there was no box or instructions. I'm sure
it was NOT made in the US, so finding the manufacturer is not gonna help
determine the proper bulbs.

[Fox's Mercantile]

On 12/26/17 5:08 AM, olds...@tubes.com wrote:
> I'm sure it was NOT made in the US, so finding the manufacturer
> is not gonna help determine the proper bulbs.

Ya know, for someone who is constantly pissing and moaning about
"Unreliable Chinese shit" you sure seem to buy a lot of it.



--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

[tabb...@gmail.com]

If they're 5mm LEDs, a bag of mixed random 5mm chinese LEDs would work. Who knows if they'll match on brightness & colour though.


NT

[Jeff Liebermann]

On Tue, 26 Dec 2017 05:08:41 -0600, olds...@tubes.com wrote:

>Thanks for the help. This is an outdoor display, but I use it indoors.

To the best of my limited knowledge, indoor and outdoor Hannukah
lights are the same.

Incidentally, look for the UL 588 label:
<https://industries.ul.com/wire-and-cable/seasonal-lighting>

>So no animals have chewed on the wires.

Assumption, the mother of all screwups. Just inspect the wiring and
see if there's any damage. You got used which means it could have
been abused in a multitude of ways.

>I dont hasve whole sections out,
>just two or three bulbs that dont light.

It could be a parallel wired affair with built in current limiting
resistors as mentioned in the patent:
<https://www.google.com/patents/US8007129>

>I could just leave it alone,
>but if it's series wired, I know it will eventually overload other
>bulbs.

Look at the way series arrays are wired. There's no way to overload
them, unless you're into shorting out the LED's that died.

>(Yea, I need to get a better look at the way it's wired).

You need to get a better look at the way it's wired.
You need to get a better look at the way it's wired.
You need to get a better look at the way it's wired.
You need to get a better look at the way it's wired.
I thought it would help if I repeated that a few extra times.

>Plus
>this was a very costly and very pretty display, so I want to keep it in
>tip-top shape. (Which is why I only use it indoors).

Costly or overpriced?

>The reason I got this, was because it was a store display, and I got it
>at a much reduced price.

Yes, but you're suppose to do that AFTER the holidays, when the stores
unload all their holiday paraphernalia. Are you sure you got a good
price, or did the store just unload something broken which they
couldn't sell?

>So, running it in the store for weeks probably
>killed the weak LEDs.

Unless overheated or run a unusually high current, LED's should last
thousands of hours. You're thinking of the bad old days of
incandescent lights, where replacing bulbs was a regular exercise.

Before you replace any LED's,
You need to get a better look at the way it's wired
and determine if there's an internal ohmsistor or current limiter.
Replacing one of those with an ordinary LED is going to produce a very
bright flash before the fuse blows.

>However there was no box or instructions.

If anything were included in the box, it would be a wholesale
repudiation of responsibility and various legal disclaimers in a dozen
foreign languages.

I originally suspected that if I did the research, I would find that
there are a few giant factories in China making both the quality and
the junk lights, which are then packaged, private labeled,
distributed, and sold by a multitude of disreputable vendors. Well,
more than a multitude. This list shows 863 manufacturers:
<http://www.made-in-china.com/products-search/hot-china-products/Tree_Light.html>
and 535,000 vendors in China:
<https://www.alibaba.com/countrysearch/CN/christmas-light.html>
Identifying your lights may be difficult.

>I'm sure
>it was NOT made in the US, so finding the manufacturer is not gonna help
>determine the proper bulbs.

There are no Hanukah light manufacturers left in the USA.
<https://www.christmasdesigners.com/blog/made-in-usa-christmas-lights/>

[tabb...@gmail.com]

On Tuesday, 26 December 2017 17:04:57 UTC, Jeff Liebermann wrote:
> On Tue, 26 Dec 2017 05:08:41 -0600, olds...@tubes.com wrote:

8<

> >So, running it in the store for weeks probably
> >killed the weak LEDs.

unlikely

> Before you replace any LED's,
> You need to get a better look at the way it's wired
> and determine if there's an internal ohmsistor or current limiter.
> Replacing one of those with an ordinary LED is going to produce a very
> bright flash before the fuse blows.

Quicker to just replace & see if they work. If the new LEDs light and the old don't, then different limited LEDs needed.


NT

[Jeff Liebermann]

On Tue, 26 Dec 2017 09:46:43 -0800 (PST), tabb...@gmail.com wrote:

>Quicker to just replace & see if they work. If the new LEDs
>light and the old don't, then different limited LEDs needed.
>NT

I was wondering what the white stuff that falls out of the sky around
this time of year might be. Initially, I thought it might be snow,
but after considering your suggestion, I suspect it might be the
fallout from exploding white LED's that were tested using your
methodology.

[tabb...@gmail.com]

On Tuesday, 26 December 2017 19:01:41 UTC, Jeff Liebermann wrote:

> On Tue, 26 Dec 2017 09:46:43 -0800 (PST), tabbypurr wrote:
>
> >Quicker to just replace & see if they work. If the new LEDs
> >light and the old don't, then different limited LEDs needed.
> >NT
>
> I was wondering what the white stuff that falls out of the sky around
> this time of year might be. Initially, I thought it might be snow,
> but after considering your suggestion, I suspect it might be the
> fallout from exploding white LED's that were tested using your
> methodology.

Lol. I doubt it. The OP hasn't a clue what he's got, the possibility of killing a 1 cent LED by overcurrent is no big deal.


NT

[bitrex]

On 12/26/2017 08:16 AM, Fox's Mercantile wrote:
> On 12/26/17 5:08 AM, olds...@tubes.com wrote:
>> I'm sure it was NOT made in the US, so finding the manufacturer
>> is not gonna help determine the proper bulbs.
>
> Ya know, for someone who is constantly pissing and moaning about
> "Unreliable Chinese shit" you sure seem to buy a lot of it.
>

Like politicians who want to ban porn because they've "done the
research" on how awful it all is. Ah, ok, definitely tell me all about
it then Mr. Expert