Hello Everyone!
I have a problem with MF01S 6500k sst20.
I calibrated temperature sensor and set temperature step down to 45C ,
after couple of minutes of worktime I measured 68c on the head of the flashlight and I noticed discoloration of couple of emitters trough the lens.
After disassembly of the head I noticed black burned out sectors on 2pcs sst20 emitters.
What is the problem with this flashlight?
Thanks.
I bypass the thermal step down manually by clicking on the switch after a few seconds on turbo. Don't feel comfortable with any of these lights staying too long on max. I don't think most of the high powered lights are designed well enough to take such a beating yet except for maybe a few, and even then, that is if the factory didn't mess up the assembly process.
Its strange that on 68c flashlight head temperature, emitters burned up.
What is the maximum working temperature for sst20?
I never had this problem with Cree,
Thanks.
The led is not the problem; it’s the interface between the led and the led board. This “reflow” is of poor quality so the led cannot dissipate its heat properly. So it’s production related.
Edit:
As mentioned above, it can also be poor/no thermal paste which will result in the same outcome. Although I question whether this is the case. I have seen too many cases of poor thermal paste jobs, yet the leds survived.
I need to change burned emitters but I dont have emitters from the same batch
Now I need to change thermal paste on all Astrolux flashlights that I have
How much current does each LED get anyway?
I count 18 LEDs and they say it does 17000 Lumen, which would be like 4 Amperes for each of these SST-20’s, wouldn’t it?
That’s quite a lot…
That means heating up the whole LED board evenly, let the solder melt and pluck off the 2 damaged ones and put new ones on there with just a tiny bit of extra solder paste.
Might want to cool it down after taking the 2 off, to add that bit of solder neatly.
Put some flux paste against the sides of all of them and reflow the lot.
Chances are you can improve all the solderings.
Do you have a temperature regulated skillet or something?
You’ll have to order 2 LEDs from Simon or BanL, i guess…
I have a heatgun btw I noticed on two more emitters that phosphor changed from yellow to brownish color so 4 emitters are bad, and after I replace emitters if the same thing happen again then I need to buy new MCPCB with emitters but I dont know where.
Too much trouble for nothing. :person_facepalming:
Thanks
I would expect more contact in the main area of the shelf, it looks like the only hard contact is around the screw holes, also looks like the mcpcb board is being held off the shelf around the outside of the shelf, looks like a possible ridge around the O.D. of the shelf itself?
SST-20 can handle 6A, I would almost wonder if there was contamination on the domes. I fried some of my first reflowed emitters that way, just some skin oils and/or thermal paste on the dome and you get the wonderful smelling smoke and soon a fried emitter.
Take the board and clean it, then lay it on a flat pane of glass or granite or any known flat surface, see if it spins, or is bowed up around to outside edge… check to see if it is flat…
btw I noticed on two more emitters that phosphor changed from yellow to brownish color so 4 emitters are bad, and after I replace emitters if the same thing happen again then I need to buy new MCPCB with emitters but I dont know where.
