The Incredible Holiday Light Show by Gemmy - LED replacement question

**KenDude** · 11-22-2009, 10:13 AM

I'm not sure if this is the correct forum to ask in, so please forgive any newbie mistake.

In 2007 we purchased a Gemmy "The Incredible Holiday Light Show" from Costco, it consists of 3 trees with globes on them that have LED lights inside (I haven't opened one but I assume at least a red, green and blue elements of some sort given the 10 different color combos the globes emit) the lights go to music that comes out of a speaker that also comes with the display.

Our family really liked it but inside of the globes a few of them have had an element or whatever you call the discrete LED go out. So for example if during the display the bulb is supposed to light up green and the green element is out, it doesn't light at all, and then at other times when the green is mixed with other colors the color comes out wrong because that specific LED is out.

I've tried to reach Gemmy without success and their website has no information on the product. Does anyone know if it is possibe to replace the entire globe or even just one of the elements/LEDs inside of the globe to get it working correctly again? I'm going to see if I can open up a globe and take a picture of what is inside and upload it here for reference.

**budude** · 11-22-2009, 10:35 AM

First of all - - Welcome to DIYC - this is a great place and lots of helpful folks here!

It's probably unlikely Gemmy sells replacement globes/parts for it. It's possible it may just be some loose connections here and there. If you can get one apart (without a hammer :p) then you can better determine what's possible from there. The only minor problem with replacing an LED here and there is that LED brightness can vary a lot so it may not look quite right when you're done. But with that said - it will probably look better than no color! If you get it apart takes some pictures and we'll see what's what...

**KenDude** · 11-22-2009, 12:00 PM

Here are a couple of photos that I snapped showing the LED's inside of the globe and how they are wired up. Any suggestions?

Oh wait I see I have a reply, thanks for the welcome, here are the pics!

**budude** · 11-22-2009, 01:02 PM

That doesn't look like it would be hard to fix. The LEDs are opaque to provide a more diffuse color pattern (w/o it you would get a spot of light). You might want to look through the Mouser catalog for possible matches. It appears there is some black around the power connections - does that look like it happened during the assembly or after?

Anyway - you can do a quick test of the LEDs by using a 2032 watch battery across the leads (unless it is shorted or something) - try it both ways to check (it won't hurt the LED hurt to connect the battery backwards). If it lights but the Gemmy controller doesn't light it, then you'll need to start troubleshooting back to the controller. If you have a multimeter you can measure the voltage across the LED leads when you run the Gemmy and see if anything is coming out. If not, well -- then you may be looking at something more extensive...

btw - it appears there is a diode on the back - can you tell what it connects to? My guess is the red LED to drop the voltage but might be good to know.

One thing you can try if you find the LEDs bad are to buy regular LEDs of the same color and sand them a bit all the way around - this will diffuse the light fairly well also.

**BuzzKill** · 11-22-2009, 03:26 PM

Diffuse LEDs will be easy enough to order. But most places on that we use around here use water clear. The other issue you will have with finding a replacement is determining the MCD or micro-candella rating for the LED. This is the "lumens" or amount of light the led puts out. It may take you a few tries to find the right rating. If the MCD rating is too high or too low, the colors in the globe will not blend properly.

But I agree with bdude. Check to make sure it is the LED first. You can just use some scotch tape to attach some small wires (A few inches of the strands inside a cat5 network cable would be perfect) to the top and buttom of a 3v button cell. Then touch those wires to the leads of the LED to see if it will light. If it doesn't then you can proceed with trying to find a replacement. Get some good solder wick or a solder sucker from Radio Shack to help with removing the bad LED.

Good luck!

**kostyun** · 11-22-2009, 05:14 PM

Based on what I remember from seeing that LED tree at costco - my guess is an LED around 4000-8000 MCD should work fine.

If it truely is a bad LED - it will be a fairly simple repair.

**KenDude** · 11-23-2009, 03:48 PM

Thanks very much for the replies thus far. I took the time yesterday to set the display up again and fired it up. All of bulbs lit up and I watched the show and sure enough there were times when a bulb was say purple or pink when it was supposed to be something else so naturally I thought that one of the LEDs must be out and thus the blend isn't right. However, in at least one instance I watched the display concentrating on that bulb and when it was supposed to be green it was green, when it was supposed to be red it was red, and when it was supposed to be blue it was blue. Ugh, it would seem that all 3 LEDs inside must be working but that something is "off" in the blending somehow, caused by a faulty LED that isn't as bright anymore or somethign else I don't know. I am going to identify one of the bulbs where it looks this way and pull it apart next weekend when I have some time and see if I can light up each LED individually with the watch battery method and see if they are equally bright or if one looks significantly dimmer or something like that.

**Entropy** · 12-21-2009, 02:18 PM

Originally Posted by BuzzKill

Diffuse LEDs will be easy enough to order. But most places on that we use around here use water clear. The other issue you will have with finding a replacement is determining the MCD or micro-candella rating for the LED. This is the "lumens" or amount of light the led puts out. It may take you a few tries to find the right rating. If the MCD rating is too high or too low, the colors in the globe will not blend properly.

But I agree with bdude. Check to make sure it is the LED first. You can just use some scotch tape to attach some small wires (A few inches of the strands inside a cat5 network cable would be perfect) to the top and buttom of a 3v button cell. Then touch those wires to the leads of the LED to see if it will light. If it doesn't then you can proceed with trying to find a replacement. Get some good solder wick or a solder sucker from Radio Shack to help with removing the bad LED.

Good luck!

MCD rating is highly dependent on view angle. Nearly all "standard" form factor LEDs have approximately the same luminosity rating - they are all rated for a forward current of 20 mA unless explicitly labeled as high power units. The only reason the MCD rating changes is usually the lens design - the narrower the beam, the higher the MCD.

http://evilmadscience.com/partsmenu/89-led has a lot of diffused LEDs, however EMSL doesn't appear to have diffused 5mm single-color units. Just 10mm, 3mm, and 1.8mm - the pictures above look like 5mm LEDs.