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FrozenGate by Avery

LPC-815 and rkcstr micro-drive v3

A

arcaneinsomniac

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May 6, 2011
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Hi all,

This is my first laser build. I don't have a host yet but I wanted to try to get a laser up and running first so I can assure myself that I can do it.

I ordered this and this.

I'm using about 8.1v from a li-po battery (using 2 cells) for power.

At first I had it lighting up, but it was very dim, even when I turned the pot up a ways. I knew that something wasn't right because I was getting nowhere near the output I'm supposed to. Before I tried to take measurements of the current with my DMM I noticed that some solder which was on the + pin on the diode was bent down and just barely touching the rest of the metal (which is the - terminal of the diode), so I figured that must be the problem! I gently pried it away so it's no longer in contact. I haven't done anything else, and now I can't get the diode to light up at all. No current seems to be flowing through the thing. I didnt pull it that hard and it's hard for me to believe i dislocated the + pin by doing this.

Is there some way I can see if my diode is dead? I know the rkcstr driver is working, I can measure current through it by connecting it through the DMM, I can try to come up with a test load by hooking up some LED's and a resistor, but I'm pretty sure the driver is not the issue. But, as I understand it, the only way to see if a LD is still functional is to hook it up to a driver...

So I guess I'm trying to figure out what the next step is at this point. Assuming the diode is dead, how do I pry it out of the aixiz module? It looks wedged in there pretty good.

I guess I oughta buy another diode and keep testing?

Edit: Also, not related to this, but another question.

If I get a 445nm diode (which is capable of handling much more than 440mA as we all know) I can still power it off of the rkcstr, correct? I just won't be able to drive it as high till I upgrade the driver.
 
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So I did more tests. Doesn't look like I'm gonna get any sleep before these final exams anyhow.

I found a 3.3v power supply (in fact it was an Arduino) and connected an 10Ohm resistor in series. This ought to pump no more than 330mA thru the circuit. I hooked that up to a DMM, it went at .256A. Okay. Hooked the diode directly up to this. Still no red light comes out. So I think the diode is dead.

I'm thinking about taking the diode out of the aixiz module and trying to visually inspect it. I have seen some other pictures that have been posted here of bare diodes but I'm not really sure what to look for. And I really don't have a good enough camera to take a good picture of that tiny thing. Any ideas?
 
I can't get a good enough look at the second tiny wire at the bottom to see if it's fried. My hunch is that it is, since the diode is not acting like an LED at all, no light comes out. I have a crappy 4x magnifying lens on my soldering station. It's not good enough. I can view through the aixiz lens but it focuses on the top of the semiconductor. Need to screw it down more to see below that, and I can't. I can see very clearly the top tiny wire and how it connects to the silicon... it's a very smooth surface... anyway I do need to take it out of the module to get a better look with that lens. However it's really really wedged in there good. Gonna take a hammer to it.

Edit: Sorry about all these repeat posts. I'll just edit this one for now.

So the hammer did the trick. I held the aixiz module with pliers and knocked on a big allen wrench (which rested on the *relatively* solid big metal part at the top of the diode) to get it out of the module. It did fall to the floor onto carpet but there was not significant trauma. At any rate I can now visually confirm the second tiny wire is not connected from the pole to the semiconductor. So I guess it got fried.

I can definitely see why these devices are so sensitive. The wires must be just mere microns thick, or maybe not even... How am I supposed to prevent ESD when not working in a space that has lots of metal things to ground myself?
 
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If there is no place to connect a ground strap I would get some anti-static spray and follow the directions on the can it realy works.
A conductive mat will help also as your hands touch the mat and the part is laying on the mat so when you pick up the part you and the diode are at the same potential. here is how mine is set up, there is a large sheet of conductive foam and as you can see there is a aligator clip with a yellow wire running to the GROUND terminal on my power supply the ground wire is to drain a big charge should I have one when I first sit down and touch the mat.
it will work with out grounding as I said above ;)

Get the spray it realy works !
 
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