Replacement LED?

So, its mot a Maglite? That about covers the "suitable replacement" question. That light was never meant to be serviced, and so your best bet in terms of time/cost/effort, together with the inevitable PITA factor is to simply replace the light altogether.

Peter Wieck Melrose Park, PA

p.s.: Only Maglites permitted in this household.

So, its mot a Maglite? That about covers the "suitable replacement" question. That light was never meant to be serviced, and so your best bet in terms of time/cost/effort, together with the inevitable PITA factor is to simply replace the light altogether.

Peter Wieck Melrose Park, PA

p.s.: Only Maglites permitted in this household.

I used to use Maglites, til LED torches came on the scene.

No way I would buy a Maglite now.

Gareth.

So it has a boost SMPS?

Make good billy clubs, the larger ones. :->

So, its mot a Maglite? That about covers the "suitable replacement" question. That light was never meant to be serviced, and so your best bet in terms of time/cost/effort, together with the inevitable PITA factor is to simply replace the light altogether.

Peter Wieck Melrose Park, PA

p.s.: Only Maglites permitted in this household.

I used to use Maglites, til LED torches came on the scene.

No way I would buy a Maglite now.

Gareth.

Oops, just discovered Maglite do LED's.

My old MiniMaglite wouldn't do 2 gigs on one set of batteries, and I would regularly have to replace the bulb too, and the switch would always need maintenance. Very expensive running costs, very time consuming, but good for hammering in nails etc.

Gareth.

Maglite makes LED units as well. The also stand behind their products....

Peter Wieck Melrose Park, PA

That's probably a downconversion phosphor. White LEDs are really blue LEDs with a blob of epoxy on top, loaded with yag powder that converts some of the blue to yellow.

I beg to differ with your diagnosis. Unless the LED has magically turned into a thermostat controlled flasher, it's not going to do that. More likely, the LED driver circuit is doing the flashing. Based on zero detail about the actual flashlight, my wild guess(tm) would be the big electrolytic that usually goes across the battery. Broken or badly soldered connections on the driver PCB are also likely.

If it's not too much trouble, could you disclose the maker and model number of your flashlight? Extra credit for providing a link to the manufactures web site or China source link. If there are no numbers or sources, perhaps a photo of the assembled flashlight?

Yep. You're looking at the wrong stuff. Maybe something by Cree: Nope. Ok, I give up. What the photo looks like is a common dome shaped LED (as in the Cree URL above) with a lens over it. I did some Googling looking for the lens and couldn't find it.

I have one that meets your requirements. L3 Illumination L10: Single cell, very bright, tolerably priced, small, adjustable brightness, etc. However, there's a catch. It has 4 brightness levels set by twisting the two sections of the body. No problem except that it makes it a two handed operation. I would have preferred a push button at the back end. I've also measured the brightness (using my highly creative and non-standard procedure) at about 90-110 lumens (varies with temperature).

Again, I don't think it's the LED. The driver board is a more likely culprit. Put it under a magnifier and see if you can find the broken trace. Put a light behind the PCB to make it easier to see the break. If desperate, trace out the schematic and try to identify the LED controller chip. If it uses an MLCC capacitor, use a hot air gun to reflow, not a soldering iron tip.

You might also get some help in CandlePowerForums:

Good luck.

Caused havoc in a Mesa Boogie amplifier when most of the dropping resistors for the 20 odd LED/CdS cell opto-couplers were the wrong value, by a factor of 10, resulting in almost 100mA of drive current.

.... Phil

Nebo NU15J:

I like this model for its good trade-off between brightness and battery life. Might be ?better?, but this fits my needs. (And it ft fits in my pocket along with my micro Swiss army knife...)

No controller chip. Looks like a boost converter (inductor, BJT, schottky diode, ceramic cap).

I scoped the voltage across the LED: it's constant 4v (with a very small--20mv?--rise and fall as it switches on and off). Haven?t yet measured current. Surely if there was a bad solder joint or other failure it would show up here.

Thanks for the referrals of other lights, but I?m not buying a replacement. I?m doing this for fun and to learn.

Cheers.

Thermostat controlled flasher is probably the exact description. It happens when LEDs are driven straight from batteries too, and is probably the bond wire heating and cooling making intermittent contact at a few Hz.

I have a cheap LED torch which uses nine parallel connected white LEDs running directly from 3 AAs. After a battery replacement, one is out, four flash at different rates, and four are on.

Cheers

Bit like sighting the Loch Ness Monster.

Bonding certainly seems to be involved and LEDs are very sensitive to high temps - way more than silicon semiconductors.

Gallium arsenide is even whimpier than Germanium, lifespan deteriorating quickly above room temp.

.... Phil

Desolder the original LED, carefully , as balance of probability it will be fine. Jumper in any old high power LED and see if that flashes too.

Circuit:

which is identical to the application note in the datasheet (scroll down to the ME2108A diagrams):

(easily translated via Google, but a bit more confusing...)

Measured current at the battery terminals is 275 mA (due to meter insertion loss it?s difficult to get an accurate current reading at the LED?s terminals--the LED dims). Voltage across the LED is a pretty-constant 4v. Estimating the efficiency of the converter at (roughly) 75 percent the LED is using 825 mW.

I guess I?m looking for a 1W replacement?

How?s my math?

Thanks.

Looks like the flashing LED is a common problem:

Some day, someone will design a flashlight with an automatic PWM light dimmer. Shine the light at something bright, and the flashlight runs at full brightness. Shine it at something in the dark, and it goes to fairly dim.

Yep, that's about it. No controller.

Ok, I'm wrong. The flashing is not caused by the non-existent controller chip.

Like I mumbled previously, see if there's a dome type LED under a plastic lens. You'll probably need to unsolder the LED leads to do this. If they really are two parts, it should be possible to find a replacement LED.

If you can't identify the LED by the power output, try measuring the current drain with a new battery. Multiply the current with your measured 4V, and you should get the power in watts. That should tell you if you should be looking for a 1/2, 1, or 1.5v LED.

Jeff Liebermann sez:

That?s my post on canblepowerforums.com. (c:

lens. You'll probably need to unsolder the LED leads to do this. If they really are two parts, it should be possible to find a replacement LED.

Will do.

You mean 1/2, 1, or 1.5 *watt* LED, yes?

Thanks.

Oops(tm).

Oops 2.0(tm). I was in a rush to get out of door. Sorry. Also, I just noticed that there is no such thing as an individual 1.5w LED.

Didn't you say it used a *single* 1.5 volt AA cell? I think that would make it 412 milliwatts not counting the conversion efficiency, so more likely a 1/2 watt LED.

I think this is an under-used(?) 1W LED.

unit. That way can dissipate some W.

But that presents its own set of problems. Optics will need to be matched to the new LED.

Hmm...