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lpc826

midnighttattoo

midnighttattoo

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Can anyone help me throw any light on this.
I recently built a small hand held laser. I bought the diode, an LPC 826 diode from odic force
The driver was a round linear 315 ma unit from Mohgasm.
The battery was a single 16340 ultra fire.
the host was a powerlight b50 with a chunky heatsink.
I was told the diode was a 200 to 300 mw unit and recommended current was 200 to 400 ma given adequate heatsinking.
I used careful soldering and heat sink compound around the module and heatsink.
The unit functioned well at first but only gave 125 ma. but it was stable and generated very little warmth that I could detect.
after about an hour or so of trying it out it suddenly dimmed and I think its what experts here may call led Ing.
I should like some ideas of why this may have happened before I try a new diode. any help would be most appreciated.
Many thanks https://www.dropbox.com/s/73vj9f82qhp8dbr/2013-05-13 20.33.31.jpg
 
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Ummm did you take the heatsink off? To me it looks like your heat sink is what the driver is in and its flipped the wrong way. If you didnt have a heat sink on the diode then you prob roasted your diode. Could be wrong since im viewing it on my phone so its smalle
 
no just took it apart for the picture
It was all together the module was grub screwed into the sink as normal and the driver was the other end

just stood it on top ..haha cant believe even I would do that.
 
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Yeah personally I see the same thing unless you just used the heatsink as a stand to show off the laser. In any case it the heatsink was upside down than the laser couldn't have been assebled...
Also what are the run times you gave your laser?
 
No its taken apart and just stood on top of the sink :-) the longest I ran it was maybe 90 seconds between turning it off and on .Changed the battery for others before I took it apart
 
Than it makes no real sense. Did you move the laser from the host with the battery in it? Ok let me try to explain, did you dissasemble the host while the battery was still in it and took it apart from the top? Just asking because something similar happend to me and it was a small short while taking the host apart and not removing the battery first.
 
No not that I recall the only thing I can think is that maybe it got too close to something and I had reflected light get in ? Its a shame because I was enjoying having this little laser and it dimmed whilst it was turned on like that battery suddenly duffed out but it was almost fully charged .. also was surprised it didn't make more than 125mw
 
Could just be a bad diode, I've run an LPC-826 at 515mA for countless hours with it staying alive. Those diodes are pretty tough.
 
You didnt use heat shrink on the outside of the module, did you? I cant quite tell from the pic, but it looks like there maybe something coating the module?
 
No I didn't put any shrink around the diode module..
Ive been as careful as I can be and made a couple of 445s before which seem to be reliable and work well I just hate not knowing really. maybe those Chinese batteries are spikey? I see what you mean in the pic it does look like a bit of shrink its just remnants of heat sink compound reflecting
 
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I think the problem is that its a linear driver meaning that you need 2 cells to get the correct power? I've got the moh driver at 568mA powering a LPC-826 in a C6 and it works just fine with a 350mW output.
 
I have to assume that he bought the whole kit at survival lasers and they sent him the correct driver for the diode. Anyway he said its fried so....
 
I've been watching this tread but couldn't post because of a ban. But he didn't get any of this stuff from Survival laser because they don't sell that host/heatsink or driver, and he said he got the diode elsewhere.
 
it does take 2 batteries (@3.7V) to run that driver. i don't think one cell would have killed the diode tho. could the driver die from running it like this with an lpc?
 
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I don't think the diode could die from under driving it. I don't think the driver would be hurt from under driving either because its a linear driver.
 
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