On Tuesday, 26 December 2017 11:09:33 UTC, wrote:
On Mon, 25 Dec 2017 14:18:44 -0800, Jeff Liebermann
wrote:
On Mon, 25 Dec 2017 14:34:36 -0600, 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?

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.

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.

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.

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