# Smoked SST-90



## lightliker (Oct 30, 2011)

After reading many posts of self builters I thought: "well, why not take a chance!" and ordered a SSR-90 at AMU-electronics in Germany. The package came in within a week after ordering :thumbsup:

When measuring it with my Fluke79, I didn't got a reading (resistance infinately) nor saw the LED glowing up, a bit strange because the at the same time arrived XM-L leds did glow up a bit when measured by the Fluke79.:candle:
Since I red that the SST-90 needs about one amp to start up, I ignored this fact and started soldering wires at the star board.

One of the four connections I didn't like so I desoldered two of them and went on with screwing the star on a CPU couler with a therman capacity of at leat 50 Watts.


Since the powerbuck driver (ordered previous week at cpf) *should *have landed at my front door, I used a 700 mA driver in order to start really slowly on this baby.
Nothing happened so I tried the 3A conlux driver, ordered at dotlight.de

Guess what: nothing happened too...


Now I started trembling and decided to measure the LED.
My nightmare came true: 0,6 ohm, the resistance of the wires of my Fluke 79!! 
I desoldered all the wires, hoping taht I might have soldered a shortcut but nothing helped at all.:sigh:
Tis morning I had some more daylight and made a macro-picture.

This doesn't look nice at all.:fail:

The poor LED did not lit up a micro second  and I took as many precousions to solder the SST-90 as quick as possible, using a weller soldering station and cooling it down right after soldering it.

Has anybody ever seen a tiny black dot in one of the lines within the yellow led-field when looking at a defective SST-90?
Could anybody take a multimeter and measure the resistance for me (my fluke79 has a special diode measuring level) to look if it glows up a bit??
Could this be a faulty LED or did I kill it while soldering it?? 

I soldered the XM-L at exactly the same way and this baby really lights u a hole room at 8 meters distance using it's own 100 or 120 degrees lense!

Any suggestions would be really appreciated!!


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## csshih (Oct 30, 2011)

from what you're writing, it seems the SST90 never was working at all!

Craig


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## lightliker (Oct 30, 2011)

csshih said:


> from what you're writing, it seems the SST90 never was working at all!
> 
> Craig



Thanks Craig, hopefully does AMU-electronics share your opinion!!
When this baby's die on me as quick as this one did, I don't know If I have the funds to get my first flashlight even starting...


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## moderator007 (Oct 30, 2011)

Did you reflow the led on the pcb or did it come soldered already. Sometimes if the solder is not making good contact between the led and pcb, the led will work but seems like its dying then sometimes stops working altogether. Sometimes it never lights up at all. The bad connection gives out under the current. If you have the led off the pcb, you could connect your driver up to the bottom solder pads on the led and see if it works then. Its possible it needs to be reflowed on the pcb. It also could be possible the led is mounted backwards on the pcb, wrong polarity.
If it doesnt work by give it power directly to the led bottom solder pads then more than likely it is bad.


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## lightliker (Oct 30, 2011)

moderator007 said:


> Did you reflow the led on the pcb or did it come soldered already. Sometimes if the solder is not making good contact between the led and pcb, the led will work but seems like its dying then sometimes stops working altogether. Sometimes the never light up at all. The bad connection gives out under the current. If you have the led off the pcb, you could connect your driver up to the bottom solder pads on the led and see if it works then. Its possible it needs to be reflowed on the pcb. It also could be possible the led is mounted backwards on the pcb, wrong polarity.
> If it doesnt work by give it power directly to the led bottom solder pads then more than likely it is bad.



The connection is short-cirquited to 0,7 ohm so any attampt of a driver will result in switching to safety-cut-off.
I try to get some pictures on a website in order to let you see what I mean.
If AMU-electronics has problems with delivering another LED, how can I desolder the LED, that is already delivered on a Star board (original luminus)?
Is the LED glued onto the board or can I just put it on an aluminium plate that is brought to a temperature of about 190 degrees celcius and take off te SST-90?
Still I think the SST-90 is gone because of the dark spot at une of the rows...
pouvre pouvre LED.......


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## moderator007 (Oct 30, 2011)

lightliker said:


> If AMU-electronics has problems with delivering another LED, how can I desolder the LED, that is already delivered on a Star board (original luminus)?
> Is the LED glued onto the board or can I just put it on an aluminium plate that is brought to a temperature of about 190 degrees celcius and take off te SST-90?
> Still I think the SST-90 is gone because of the dark spot at une of the rows...
> pouvre pouvre LED.......


You have the general idea. I usually just use a 150 watt solder iron under the aluminum pcb While pushing slightly with a small flat screwdriver, heating it up slowly until it slides off. I hold the pcb with the helping hands. Here's a good link on the reflow process.
A few other methods in this thread here. This is what the manufacturer recommends.
I think you might be right about the dark spot. Looks like that this led would have been tested in some point in time before you received it.


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## Norm (Oct 31, 2011)

Moved to LED - Norm


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## lightliker (Nov 5, 2011)

A few days ago I contacted AMU-electronics and they promised me to send a replacement LED :twothumbs:twothumbs
Way to go AMU-electronics!!!

Now it is waiting for my BuckConverter from Der Wichtel.
It arrived a week ago, what a piece of art work!! 

http://i1178.photobucket.com/albums/x368/lightliker/SST-90 adventure/IMG_2103.jpg

Strange enough there were no leads for the potentiometer so I mailed Yitao.
He was glad to know where the other mixed up driver went to and will send me the right one this weekend.

This gives me the time to think about how solder a LED even faster and look out for some reflectors this coming week.....

I'll be back 

Edit: On special request I placed a less "nude"picture of this nice driver


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## lightliker (Nov 5, 2011)

moderator007 said:


> You have the general idea. I usually just use a 150 watt solder iron under the aluminum pcb While pushing slightly with a small flat screwdriver, heating it up slowly until it slides off. I hold the pcb with the helping hands. Here's a good link on the reflow process.
> A few other methods in this thread here. This is what the manufacturer recommends.
> I think you might be right about the dark spot. Looks like that this led would have been tested in some point in time before you received it.



Thanks very much moderator007
Before even soldering it I will clamp the new LED with some springs and cooling paste to the cooling body and connect it with to needles, pressing at the contacts (the same way the test the LEDs in the factory I think.

Now I have to find some nice reflectors with the accent on flood but with enough throw. D.E. has a nice one for less than 10 bucks.
Any suggestion is welcome!!


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## ExtremeX (Nov 9, 2011)

That sucks, sounds like the vendor is taking care of you.

I killed an XM-L led just playing around wth a bench power supply / not paying attention to the voltage. Sucks, since I JUST got it after a long wait from china just to kill it right away


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## jasonck08 (Nov 10, 2011)

ExtremeX said:


> That sucks, sounds like the vendor is taking care of you.
> 
> I killed an XM-L led just playing around wth a bench power supply / not paying attention to the voltage. Sucks, since I JUST got it after a long wait from china just to kill it right away



haha I did that to an XM-L too. Upped the voltage too fast and the current spiked to 10A for a second and


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## pavithra_uk (Nov 11, 2011)

There is a way to give life to your LED again. Zapping...


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## lightliker (Nov 14, 2011)

pavithra_uk said:


> There is a way to give life to your LED again. Zapping...



What do you mean??
I sent the led back to AMU but still haven't received the replacement yet........
This weekend won't be much time so this is gonna be a long story....


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## bshanahan14rulz (Nov 14, 2011)

sometimes LEDs can be brought back to life by applying a relatively high reverse voltage across the electrodes.

edit: csshih says forward voltage, and I trust him more than my memory.


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## Mike S (Nov 14, 2011)

bshanahan14rulz said:


> sometimes LEDs can be brought back to life by applying a relatively high reverse voltage across the electrodes.



Is there a thread on how to do this? I killed one SSR-90 by connecting the positive and negative wires to both positive pads on the star and also killed an XR-E by powering it up with the source set to 12V. It sounds like it's worth a shot.


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## csshih (Nov 14, 2011)

bshanahan14rulz said:


> sometimes LEDs can be brought back to life by applying a relatively high reverse voltage across the electrodes.



well no, that's only if the die produces a conduction channel, from what I've read. I think this case either there's something more serious wrong with the die, as there's a black spot! Honestly it looks like someone had previously pumped quite a few too many amps through it as the phopshor on the left and right appear to be creeping away from the bond wires, and it looks like the bond wire detached on the upper right corner.



Mike S said:


> Is there a thread on how to do this? I killed one SSR-90 by connecting the positive and negative wires to both positive pads on the star and also killed an XR-E by powering it up with the source set to 12V. It sounds like it's worth a shot.



reverse the polarity and try to shove a few amps though it. I'm fairly sure your bond wires are disconnected, though.

-Craig

edit: oops, actually, try keeping the polarity normal.


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## moderator007 (Nov 14, 2011)

csshih said:


> Honestly it looks like someone had previously pumped quite a few too many amps through it as the phopshor on the left and right appear to be creeping away from the bond wires, and it looks like the bond wire detached on the upper right corner.


I didn't notice that when I first looked at the pic. Yes, I agree csshih. It does look like it has been over driven or improper heatsinked.


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## Mike S (Nov 15, 2011)

csshih said:


> reverse the polarity and try to shove a few amps though it. I'm fairly sure your bond wires are disconnected, though.
> 
> -Craig
> 
> edit: oops, actually, try keeping the polarity normal.



Thanks, I'll give it a try. When the SST-90 died, I did see some of the bond wires glowing right where they connect to the die.


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## lightliker (Nov 15, 2011)

Mike S said:


> Is there a thread on how to do this? I killed one SSR-90 by connecting the positive and negative wires to both positive pads on the star and also killed an XR-E by powering it up with the source set to 12V. It sounds like it's worth a shot.


With a bit of luck you could desolder the LED from it's star board (if you ordered this type) and use it with a special heatsink that is offered by one of the cpf members...
Did you measure thi pouvre pouvre LED??
I would think that only the printed connection would have been damaged by the high shortcirquit current....


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## lightliker (Nov 15, 2011)

Is there a member that could measure a SST-90 LED with a multimeter (i.e. fluke at diode measuring position)??
Since the LED hasn't arrived yet, I am very anxious to know what happens when measuring the SST-90

a) nothing at all :shakehead
b) a nice glow of the die :naughty:
c)


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## pavithra_uk (Nov 16, 2011)

lightliker said:


> What do you mean??
> I sent the led back to AMU but still haven't received the replacement yet........
> This weekend won't be much time so this is gonna be a long story....



here is the way how to do it. I did it and sucess. (not for SST-90. its samsung sunnix LED)

find capacitor around 4700 uF any voltage. charge capacitor to 4~5 Volt power source. then connect capacitor lead directly to LED (cap+ to LED+/ cap - to LED-)

sometimes you have to do few times to revive LED.

What it really do:- Once charge capacitor connect directly to LED, it flow high current pulse through shorted area of LED and fry shorted metal. 

sorry for my bad english


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## lightliker (Nov 19, 2011)

pavithra_uk said:


> here is the way how to do it. I did it and sucess. (not for SST-90. its samsung sunnix LED)
> 
> find capacitor around 4700 uF any voltage. charge capacitor to 4~5 Volt power source. then connect capacitor lead directly to LED (cap+ to LED+/ cap - to LED-)
> 
> ...



Nice advice, I thought to do something like that but was asked to return the LED to AMU-electronics, which I did.
Now I am still waiting for the replacement LED to arrive since 3 november...:sick2:
How much patience must someone have untill everybody does his work as promised..... : wrong shipments, defective leds, long shipments and even for the konlux driver I had to wait for almost a month, all coming out of Germany , so close to the Netherlands!
A 38 euro costing flashlight out of china!! arrived sooner!!


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## lightliker (Nov 21, 2011)

Guess what!
Still no shipment with LED arrived 
It's frustrating paying almost 50 bloody euro's for a defective LED and waiting now more than 5 weeks till this sucker arrives! 
Called with AMU-electronics and they ship a new one, this time with track and trace number to follow the shipment.
Hobby's take (postal) time! 

Can anybody by the way make a picture for me of a new SSR-090 LED on star??
I am asking myself IF this defective LED has been used and want to know how new LEDs are shipped from the supplier.


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## BrightLED17 (May 17, 2012)

What kind of power supply you are using? I have problem getting high current power supplies.


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## lightliker (Feb 10, 2013)

After receiving the right LED I used the handmade LED driver of a chinese guy that makes very nice buck converters, just search at SsT 90 and buck and you will find him.
However, the second LED also died on me due my own fault so I stopped experimenting with too expensive LEDs :mecry:
Case closed.


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## AnAppleSnail (Feb 10, 2013)

Start with little ones for practice. You can get olds crees for about a euro each.plus shipping in the US. Much cheaper to goof on.


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## MikeAusC (Feb 10, 2013)

When testing LEDs by connecting to drivers or power supplies, there are two things you should do - 
- connect to the LED to the power supply before switching on the supply.
- setting the maximum voltage to just a little above the operating voltage e.g. 3.5 volts for an XM-L.

If you switch on a Current-limited power supply or driver with no LED connected, the output capacitor will charge up to the input voltage (e.g. 12 volts), then when you connect the LED, the stored charge on the capacitor will cause a massive current surge through the LED (which is not limited by the current setting)

If you have a loose connection, the same current surge can happen.


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## awenta (Feb 13, 2013)

Double thread revival FTW!


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