Advice on replacing a tiny bulb in a decorative piece. (images included)

Thread Starter

newbe2018

Joined Apr 21, 2018
7
I have this lit Halloween display piece and one small bulb does work inside one of the lanterns. There are four lanterns on tree branches that light. There are another five small lights on the other parts of the tree. It uses 3 AA batteries or a 4.5 v ac adapter. The bulbs in the lantern are about the size of a pen tip with two wires per bulb.

Do you know what type of bulb this is?

https://imgur.com/PLWt6Wz

https://imgur.com/X6eS9ay



Do you think that this area could be removed with a heat gun? It seems like that would be the only way they could assemble it in the first place. The only other way I see would be the wire going out the bottom of the lantern and they solder the bulb, then pull the wire back through branch/piece?

https://imgur.com/a/NpYMGUR

Another question I have is that the bulbs are clear, but when lit they look the color of each lantern. Can these small clear bulbs be a colored bulb, or am I seeing the reflection of the lantern color on the bulb?

Thanks

BULB00.jpg BULB0.jpg TREE.jpg
 

wayneh

Joined Sep 9, 2010
16,399
Those are LEDs and they could absolutely be colored. You can’t tell the color of an LED until it’s powered on. Sorry I can’t answer the assembly question.
 

wayneh

Joined Sep 9, 2010
16,399
Thanks guys. I finally removed the outer lantern part (used a hot knife and came right off). Here are some better images of the bulb. So would you say they are LEDs and does it look bad or could it be the wire?
Again, there is no question that those are LEDs, and most likely they are 3mm as @Dodgydave suggested. Your photo shows that they appear to be about 1/8" in diameter, which is very close to the standard 3mm size.

You usually cannot tell by looking if an LED has gone bad. Do you have a multimeter? If there's a voltage across the leads of an unlit LED, something around 3 volts, then the LED is probably bad. But if it failed to a short, there won't be a voltage there. So it can be tricky to be sure what's happening. If it was me, I'd unsolder one lead of the suspect LED and insert a know good one to see if it lights. Be watchful of polarity if you try this.

In most of my solar lights out in the yard, failure is due to corrosion of the wires or circuit board. It's rarely the LED itself that fails.
 

Thread Starter

newbe2018

Joined Apr 21, 2018
7
Ok, so I ended up removing the bulb. Tested it and it lit up with a multimeter. Held a new bulb to the wires where the old bulb was on the tree and did not light up. Looking from the underside there are a bunch of small "diodes". I take it was one of them is bad?
 

wayneh

Joined Sep 9, 2010
16,399
Ok, so I ended up removing the bulb. Tested it and it lit up with a multimeter. Held a new bulb to the wires where the old bulb was on the tree and did not light up. Looking from the underside there are a bunch of small "diodes". I take it was one of them is bad?
Diodes? They’re more likely resistors but it would be good to see a photo.
 

Thread Starter

newbe2018

Joined Apr 21, 2018
7
Diodes? They’re more likely resistors but it would be good to see a photo.
This is what they look like. There are two on the bottom, that I think go with the two bottom lights. Then two up the tree trunk that I think go to the lights on the treehouse eyes and mouth. The lanterns resistors I think might be up further :( I might be able to use a hot knife at the bottom base of the treehouse and remove that glue but I think if I lift the treehouse section the wires going through the branches will stop me from removing the treehouse section, unless they are long enough.

Clearer image of the resistors and all the lights on the piece

Using a endoscope to see inside the trunk
 

wayneh

Joined Sep 9, 2010
16,399
I feel like I just watched a colonoscopy! Of someone that’s been eating resistors. That’s all I saw, resistors.
 

Thread Starter

newbe2018

Joined Apr 21, 2018
7
I feel like I just watched a colonoscopy! Of someone that’s been eating resistors. That’s all I saw, resistors.
:D

Would you think each one of those resistors controls just one bulb/wire? Do resistors have different sections that can go bad?
 

Thread Starter

newbe2018

Joined Apr 21, 2018
7
The glue or sealant on the underside of the treehouse part would not come undone with the hot knife, it was chipping away. Not sure what material was used. Decided to just remove the one lantern, guess three is good enough.
 

wayneh

Joined Sep 9, 2010
16,399
:D

Would you think each one of those resistors controls just one bulb/wire?
That's what I'd expect but it's not absolute - whoever built this could have done just about anything. One thing that comes to mind is using more than one resistor per bulb, to tweak the brightness of the different colors. There's just no way to know for sure without careful examination and taking measurements.
Do resistors have different sections that can go bad?
Not usually, no. If it goes bad, it's usually because it blew like a fuse - a catastrophic heat level destroyed the whole thing. You can usually detect this by visual inspection. If it looks OK, it very likely is OK. Resistors rarely "go bad".
 

Thread Starter

newbe2018

Joined Apr 21, 2018
7
That's what I'd expect but it's not absolute - whoever built this could have done just about anything. One thing that comes to mind is using more than one resistor per bulb, to tweak the brightness of the different colors. There's just no way to know for sure without careful examination and taking measurements. Not usually, no. If it goes bad, it's usually because it blew like a fuse - a catastrophic heat level destroyed the whole thing. You can usually detect this by visual inspection. If it looks OK, it very likely is OK. Resistors rarely "go bad".
Thanks
 
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