I've only done post mortem on one bulb. What I found was (what I originally though was a fuse) was a (probably) 10 Ω 1/2 watt resistor had burned to cinders. I haven't messed with the second one yet, but it's failure was peculiar in that after removing it when I set it on the table it flashed. So I tapped it a few times and each time it flashed. So I'm expecting either a broken wire or a failed solder joint. Perhaps I'll photo document its disassembly and autopsy. Normally I'm pretty bad at documenting things. I'll try to do better on this next one. After all, I am curious as to failure mode.

The first failure was in a unit that was absolutely ventilated. The second was unvented, so it's probably a solder joint. The bulb WAS too hot to hold continuously. I HAD to put it down quick. Hence, the flash on the desk.

They usually have a reservoir electrolytic smoothing the supply to the LED chain, if the LED chain is intermittent; the cap can charge to well above the combined Vfs. Whenever the break makes - it dumps into the LED chain and something is likely to pop.

 

OK, it looks like it fixed itself. No - really. The second bulb to burn out is now lit on my test bench right now. Remember, when I pulled it from the fixture it was almost too hot to touch. Well, it's cold now and glowing happily. I'm SURE it will fail again, I just don't know when. So for now - no post mortem exam's. After all, it's not dead (at present). But I'll give it some time. Meanwhile I'm going to mess with something else. I'm considering building an air core pancake coil to transfer power from a stationary source to a moving source (rotating). I can transfer power via brushes but I'd rather go for something a little quieter. I may even post a question or two concerning that project. For now, this is about the wayward LED that could, then couldn't then for some unknown reason, it can again.

Oh, the replacement ? ? ? Instead of 13 watts it's only 12 watts. So they've replaced it with a slightly lower wattage. Certainly nothing I can readily discern visually, but I DO think I can detect the slightest difference in brightness. They are the same color, 5000 Kelvin.

Also, the replacement it's a plastic body whereas the original failed bulb is aluminum. If that means anything. And it's getting hot fast. In open air no less.

 

The second bulb to burn out is now lit on my test bench right now.

So not only can you get light out of dead batteries you can also get light out of dead bulbs?
Burn the witch!

 

SHUT UP AL!

Oh, incidentally, the one coin battery and red LED are still glowing, but very faintly.

 

If you know how to build PCB project i suggest you to make your own AC/DC board and replace the crappy one inside the bulb you bought.I did that on all my bulbs and i believe they will work for a very long time.Problem is manufacturers put cheapest components and all that components work on edge of their abillity.If you try to make and replace AC/DC board make shure you buy bulbs that can be disassembled easy.

 

Well, basic AC theory is a bit over my head. As for building something of my own and putting it in the tight confined space they put theirs in - well, I can't imagine how to go about that.

14 minutes into my burn-in test on the bad bulb and it's still lit.

 

It's been an hour running the failed LED and no signs of problems. I have other things to do besides sit here and babysit a lightbulb.

˚J˚
¬

 

It's been an hour running the failed LED and no signs of problems. I have other things to do besides sit here and babysit a lightbulb.

˚J˚
¬

We all do, that's why we're here on AAC! ....no, really, I used to have a life!

 

It's been an hour running the failed LED and no signs of problems. I have other things to do besides sit here and babysit a lightbulb.

˚J˚
¬

Where I live; a store is selling =60W LED bulbs for £1.30 and =100W for £2.49 - I wouldn't bother repairing one, I already know what's in them and not much of it is worth salvaging.

 

Out of interest,I have seen the same sort of effect.

I have all most all bulbs as leds now,

I purchased three separate batches from different manufacturers / suppliers over the years,

I have one batch, that after a year or so, start getting dimmer , start flashing, start getting hot.

The other two batches, one older,one younger, are all fine,

Annoyance, is that first batch are fine, put them in easily to reach units, second batch that are failing, some are in real hard to reach spots, which is why I went for leds.

 

Annoyance, is that first batch are fine, put them in easily to reach units, second batch that are failing, some are in real hard to reach spots, which is why I went for leds.

Isn't that the way it always is ? ? ?

I wouldn't bother repairing one.

Not interested in repairing any of them. Just out of curiosity I want to have a look at how they did what they did. Y'know, the first Sylvania's have aluminum housings. The replacements don't. They're plastic. So I'm wondering what's going to happen if these run as hot as the others did. I can't imagine anything good coming from it, but time will eventually tell. NO ? ? ?

 

Isn't that the way it always is ? ? ?



Not interested in repairing any of them. Just out of curiosity I want to have a look at how they did what they did. Y'know, the first Sylvania's have aluminum housings. The replacements don't. They're plastic. So I'm wondering what's going to happen if these run as hot as the others did. I can't imagine anything good coming from it, but time will eventually tell. NO ? ? ?

CFLs got plenty hot, the worst effect I've seen is discoloured plastic. I used to smoke - so that would have contributed most of the discolouring.

 

This is interesting. I have dozens of LED bulbs around my home and most have been installed for between 2-3 years so far. Most are FEIT brand and all claim to last over 20 years. I just exprienced my first failure. It was the one and only Slyvania bulb I bought because it was the first I found to put out the lumens close to a100 watt incandescent to go in a lamp on my bedroom dresser. It was the exact Sylvania model LED19A21/DIM/0/827/G3 bulb that failed for you. It is an extremely heavy bulb compared to similar lumens by other manufacturers that have come out more recently. I bought this one about 2 or 3 years ago and it doesn't get but 2-3 hours use each night.

 

It was the exact Sylvania model LED19A21/DIM/0/827/G3

I went on the Sylvania website and told them what happened with mine. They replaced it free of charge free of shipping costs. The one I took apart had an aluminum heat sink body and the electronics inside were potted in with a white soft rubbery material that was easy enough to pick out of the board. The failure on mine was a resistor connected directly to the center probe of the socket. At first I thought it was a fuse but actually it wasn't. It was (as I've come to learn) a 10Ω 1/4 watt resistor, shrink sleeved and potted in.

Sylvania said if you put their bulbs in an unvented light fixture they will overheat and fail. Looks like overheating was the cause of my failure. However, the bulb was in an open lamp, shade around and below but wide open on the top. So yes, it did overheat, but not because of being in an enclosed fixture.

I had another bulb fail that WAS in an enclosed fixture and just the other day I've had another fail. All are Sylvania's bulbs. If nothing else, they ARE interesting heat sinks, but a painted heat sink (which they are) can't dissipate heat as well as purely anodized aluminum. This I know from having painted a gasoline engine and the darn thing started overheating. Why? Because I painted the cooling fins. LOOKED pretty. Ran like crap afterwords. Scrap engine - what do I care.

Sylvania - you'd have thought they'd make a good product. I guess like many other things, the bean counters are finding cheaper ways to manufacture product - but at the cost of reliability. That's what makes companies go under - bean counters who have no practical world experience. A happy customer tells 5 others. An unhappy customer tells 10 others. That's 15 people a company won't see as customers AND the loss of the one unhappy customer. 16 people in all. And how much does a lifetime customer spend? Well, when it comes to LED Lights - I've probably spent a couple hundred bucks re-lighting my house with LED's. That's a potential $3200 bucks lost because of one unhappy customer. That's probably why they sent me a new bulb so fast. But if it's like any of the others - it'll be failing in another year or two.

10 years - indeed!

 

I had a Philips LED bulb (the weird looking yellow one that was one of the first) that had a 6 year warranty fail after 4 years. I tried contacting them several times with no response other than them spamming me for unrelated stuff.

I'm happy with Cree. They replaced 3 bulbs that failed promptly and with no hassle. I have no concerns continuing to buy from them.

 

bulb quality varies dramatically between brands, and models of brands. if you dont want problems, you need to pay for it. Cree prides themselves on quality, as does Hyperikon and Phillips.

 

I have nearly all LED bulbs in the house. So far I've had a Sylvainia bulb burn out, less than one year. Just now a second bulb burned out, maybe in service for two years - another Sylvania, and not that many hours on them. Smaller than the other one, but it burned out nonetheless.

At first I tapped it. It flickered. So I removed it and set it on my workbench. It flickered there too. Tapped it a few more times and again it flickered a few more times. It no longer flickers, the capacitor inside must have discharged.

Anyone else experiencing LED bulbs burning out? They tout that they're supposed to last 10 years. OK, the LED part of the bulb will likely last that long, but the electronics inside them are burning out far short of the 10 year proclamation. The first bulb to blow, it appears the main fuse internally has burned out. I took it apart and de-potted it. Also damaged the LED element so I couldn't put it back together, but nevertheless, it burned out. OR perhaps more appropriately expressed, "Failed".

These things aren't cheap. They're SUPPOSED to last 10 years. This is really bugging me. ESPECIALLY with Sylvania. I thought they were one of the better name brands. Does this mean ALL my LED bulbs are unreliable? I don't have exclusively Sylvania, but most of them are.

Maybe I should call them and complain.

[edit] and hot as hell too. The heatsink that is.

Hello Tony,
I just found your entry this morning (I know it's an older post) and am wondering if you ever got any satisfaction from Sylvania. I've just had 2 PAR16 go out within a couple weeks of each other and have at most 8 to 10K hours on them. Mine appear to be failing capacitors in the power circuit, they flicker on an off, initially on more than off but now to the point that they are off more than on and is definitely not an overheating problem as they are pretty much open to free air. And you are right, these were not cheap bulbs...

 

Cree prides themselves on quality, as does Hyperikon and Phillips.

My experience with Phillips has been unsatisfactory.

No contact regarding my bulb that failed under warranty, but a lot of junk email for unrelated products.

 

It's been a while but I believe Sylvania sent me a new bulb or two. Like I said, it's been a while and I don't remember all the circumstances. But generally yes, I've been satisfied that they honor their warranty.

 

So, without tearing any apart, what's the current, typical scheme? My guess is:

- high speed SS switch cutting the wave for just the voltage and polarity desired

- power switching controlled by a chip built for that specific purpose (wave chopping power supply).

- multiple LEDs to achieve the desired lumens/lux

- LEDs in parallel strings with resistor and cap


If they're doing it by wave chopping instead of transformers, how are they "dimmable" when installed replacing tungsten, and with the typical wave-chopping wall dimmers? Does the "CPU" monitor the source waveform and base its output wave on calculated power value of that input waveform, as well as switching some individual LEDs off entirely to get a decent dimming range?