240V ac LED bulb failure

[debe]

This is not about repair as it had to be destroyed to dismantle. The bulb was only about 8mths old when it started flickering then failed. It uses a solidstate chip to regulate current, & there was dry joints on the circuit board like found on SMPS. The circuit board was set securely with a soft grey rubbery compound. The LEDs are mounted on an aluminium disk as a heat sink. Pictures & circuit of the unit.

 

[Bluejets]

There are many claims about the thousands of hours the new generations of LED lights will last.
How they know this is at best I imagine a guestimate.

One thing we have found dealing with many differing type of lED fittings for mains connection is that it is invariably the drivers that fail.
When they do, one has to chuck out the complete unit as for a start, drivers alone can be difficult to obtain in some instances, and apart from this, drivers when purchased seperately from a "complete fitting" usually cost more than the latter.

At $1.00 a pop, maybe the tungsten bulb wasn't so bad after all.

More to come though as fluros (all types) are the next on the endangered lineup.

It is amazing though, how much they can stick inside a bulb casing these days for maybe $10.00

 

[debe]

Ive found these cheepies $2 ea more reliable as they are simpler in the electronics department.

 

[Externet]

Poor solder joints that heat up will end arcing and arcing contacts produce voltage spikes capable of destroying any semiconductor devices.
If repair is not the subject, return it to the vendor. An attempt to repair starts by confirming the health of all LEDs by applying 3VDC to each. I would after modify the circuitry without the IC that is likely dead.

 

[BobK]

Your paying $10 for LED bulbs? They are down to about $2 here.

Bob

 

[73's de Edd]

.


Sires . . . . . . .


O.K. this last shown unit seems to be the KISS route to go, with no high frequency conversion with adjunct semiconductors.

The raw AC line just comes in and uses that AC line series " voltage dropper" capacitor that "thinks" its a 3K resistor at that incoming 50~ line frequency / perceived impedance . Then it takes on full wave rectification by the quad set of diodes and then its DC power is stored in the 47 ufd electrolytic.
And then , using the phantom view of the foil, it looks like 16 series arranged LED's and possibly two surface mount resistors placed at each END of the string . . . .fine print . . . .can't read the values . . .what are they ?
It's making optimal use of what surplus copper foil there is, patterned, to get a bit of additional dispersed heatsinking for the LED's.
That electrolytic operating at line frequency should last . . . .as compared to the universally seen HF, SS drive circuits which are continually HAMMERING that DC storage cap with 10-100k's of pulses per second.
ALAS . . .the units price would have been driven up to 2.25 had they additionally incorporated a varistor for line spikes . . . .which the " bean counters " opted not to do.

Thasssit . . . . ..



73's de Edd


.

 

[debe]

You got it right 73 s de Edd.

 

[Bluejets]

Your paying $10 for LED bulbs? They are down to about $2 here.

Bob

When you get a country like Aus with an obsession with workplace health and safety ( to extreme) then as usual, the end user pays.
Perhaps why Ebay is so popular down under

 

[Mongrel Shark]

I found you need to pay at least $15 for mains fitting LED globes in Australia.
I started with $2 ones from ebay and got a bit of everything up to the $15 Phillips and Median (Aldi) globes. Everything but the $15 ones died within 12 months. The ones under $10 are all fire/electrocution hazzards. I've had 2 philips globes with driver issues that cause flickering and buzzing at start up sometimes (like when I turn 3 light switches on at once). The median brand ones are still working great 4 years later. Some rarely get turned off. Thats all I have bought in the last 2 years. Its a shame they dont make brighter ones though. 100w equiv is the brightest... I want some replacements for my outdoor spotlight globes....

one lot of corn cob style globe. Had exposed smd contacts on the outside that can shock anyone that plugs it in/out of a live socket. And runs enough leds in series that no step down is required from the rectified mains....

 

[debe]

had 2 philips globes with driver issues that cause flickering and buzzing at start up sometimes

That's exacly what happened to the one I had with the dry joints on the circuit board. It was a $12 bulb but I decided to investigate what happened rather than return it (My curiosity always like to know why something failed)

 

[Mongrel Shark]

That's exacly what happened to the one I had with the dry joints on the circuit board. It was a $12 bulb but I decided to investigate what happened rather than return it (My curiosity always like to know why something failed)

Damit. Now I really have to look in there! I have been resisting for months. Dad was teasing me too during a recent visit. Every night I'd smash the three switches open. then toggle the flickery-buzzy one till it settled. Dad would say innocently "I wonder what's causing that?" Knowing damn well the only reason its still in one piece is because I haven't had time to dismantle it and dont have a spare globe thats as cheap to run.. The buzz does sound arc like and there is a hint of ozone. I suppose I could solder it up before it dies.... Or maybe I'll just make some popcorn and start toggling the switch more...

 

[Bluejets]

Damit. Now I really have to look in there! I have been resisting for months. I suppose I could solder it up before it dies....

Debe did say it had to be destroyed to dismantle it ....

As far as floodlights go, this one should more than cover your requirement.
(there are others)...check equiv. wattage/type

http://www.ebay.com.au/itm/50W-CREE...151519?hash=item281e6cff1f:g:dkUAAOSwZVlXs-U0

Or you could always use a fitting with a self-balasted one of these....

http://www.ebay.com.au/itm/OSRAM-80...994703?hash=item23702f2acf:g:Z0kAAOSwRgJXhJ48

 

[debe]

Ive bought a few of those flood lights. They are great But on removing the back cover to fit a longer cord, I found the Earth wire is just stuck into a blob of Silicone. So you realy need to check on each one to see if the earth wire is actualy connected. When fiting the longer cord I fixed the earth wire to the frame.

 

[(*steve*)]

I found you need to pay at least $15 for mains fitting LED globes in Australia.

Or $5 from Bunnings with a pretty much no-questions asked 12 month return policy (keep your receipt).

I've taken one apart after it "failed" and found out that the problem was a bit of melted glue. the newer versions are better designed and don't suffer the same problem. Aside from the glue problem (which merely causes the LEDs to drop to the bottom of the "bulb") I have had a large set operating for a couple of years with a single non-cosmetic failure.

These are only 470 lumen, so in areas which require more light (like my office) I have higher power (1000+ lumen) brand name bulbs.

A 4ft fluorescent tube has also been replaced with a LED equivalent and I am very happy with its performance.

At my local hackerspace I have replaced 2 tubes with LED tubes and the rest with cheaper high efficienct fluorescent tubes. The LED tubes slightly out-perform them in light output, but only time will tell if they do do over their lifetime and whether the 5x cost equates into something useful. Given that the tubes are about 4m from the floor, I like not having to get up there too often (I delegate the task to others ) but I doubt that they will last 5x as long.

 

[Mongrel Shark]

I too have some of those floodlights. Great as portable work lights.
But they don’t plug into the ceiling socket in my kitchen or the sensor light at the front door, and not bright enough to de a proper day-maker.
The ones I need are like this
http://www.replacementlightbulbs.com/lamp21ar40fl12v.html
but in 250w mercury vapour equivalent with a bayonet. Thinking about using a 100w smd but the heatsinking has me stuffed. I just cant work out how to get that much light from that size package without cooking components (or the top of my head I have 6in clearance under the lights)

I have 3x 15w LED globes in the kitchen to save power (and a hot head) but its really dim in there. I have to keep re aiming all three lights to the surface I am using. I still cant do dishes at night. Its a sunny day with the lights on affair. At night the average bench top lux reading is well below 500. vs over 50k for sunlight... Ok for reading a newspaper or something bold like that. But useless for fine detail.

I often have one of these on my head at night to supplement the mains lighting.
http://www.ebay.com.au/itm/9000LM-C...hash=item5d60ae5b37:m:mRJxurtwMRtiWS9iy4iGfig

Its sort of just bright enough (up close) for an hour or so, but it gets really hot and kills 6-8ah of 18650 in 2 hours. I can't 3d print or smd solder without it now days.
I had the LUX meter out because I thought the lights where fading. Turns out its my eyes. First the LUX meter told me every day for months the kitchen was getting dimmer and the meter was staying the same Then I recently found the 10x setting on my microscope showed me stuff I hadn't seen without it. First time for that too. I always thought less than 10x was a waste of time and went straight to the 60x...... I'm only 34... It seems to be getting much worse since I got a smart phone and tablet...

 

[Mongrel Shark]

These are only 470 lumen, so in areas which require more light (like my office) I have higher power (1000+ lumen) brand name bulbs.

In a screw/bayonet fitting? Link?

 

[Bluejets]

but in 250w mercury vapour equivalent with a bayonet.

They don't come in bayonet.

I often have one of these on my head at night to supplement the mains lighting.
http://www.ebay.com.au/itm/9000LM-C...hash=item5d60ae5b37:m:mRJxurtwMRtiWS9iy4iGfig

hehehehe....think I'd be getting an eye test.....

 

[Mongrel Shark]

hehehehe....think I'd be getting an eye test.....

I did that. 20/20. I think my eyes where just really good before. I always used to see stuff most people needed magnification for. Both small and close or long distant objects.

 

[(*steve*)]

In a screw/bayonet fitting? Link?

Both, but sometimes bayonet are a little more expensive... Oh and the ones in my office are 2000 lumen (I checked).

Neither appear to be on their web site. My wife has some tasks for me that will probably get me to Bunnings tomorrow so I'll report back on the actual items

 

[(*steve*)]

Here they are!





Cheap ones are now 2 for $6. The earliest ones I bought were 2 for $15. The price keeps on dropping. Soon they'll be too cheap to bother stocking!