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So Busy a Rookie Mistake Got Me

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So, I've been very busy at work in the last two weeks, with my assistant out due to a torn hamstring. Now, usually, I have the time to handle the sales and repair of the vacuums, and get plenty of time to work on lasers.
Of course, as soon as my assistant is out, we suddenly get bum-rushed with a million repairs, and with only myself to handle it.

On top of all this, I am in the process of building five lasers for clients, two for myself, and trying to fit in fixing a lens alignment issue. I had to hand polish all three Kryton hosts that I am selling, and my latest Kryton for a single-mode 638, and I decided I had to re-polish my other two Krytons because my Tungstun ring had lightly scratched my 405 and 450nm. That's six in all for those not counting.
I haven't yet mentioned having to tune and prep a 9mm @ 2.3A and a PL520 @ 300mA to fit into two of Sinner's MS-SSW hosts!
Yeah, I'm still waiting on the hosts as well.

So, to finish this diatribe, I was tuning four Blitzbucks and noticed I had the same problem with each one; I couldn't push more than 2.3A out of any of them. I really started to worry, as I want to ship these lasers!
As I sat down to email Wolfman about the malfunctioning drivers, it occurred to me that I had set my Vf on my test load at ~6.5V. I remembered that when I was direct driving the diodes that they were only pulling 5.7V from the PSU! So, I sat back down, reset my Vf on the test load, and BAM!! Wouldn't ya know it? Each driver worked fine, topped out @ 3.1A. I set them appropriately, and could breathe a little bit easier.

I guess things are catching up to me.

Be good, y'all!
 

Sigurthr

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That's not too bad of a mistake, it happens, and you didn't destroy any silicon in the process!

I remember once I was converting a bipolar half bridge to MOSFET tech and I forgot that the pinouts were different between the two technologies. I blew up my share of expensive MOSFETs that day.

BCE > GDS, but bipolars are pinned as EBC!
 

WizardG

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"That's not too bad of a mistake, it happens, and you didn't destroy any silicon in the process!"

Who gives a flying fork about silicon? It's the gallium compounds that are the precious!
 

Sigurthr

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He was powering the drivers, not direct driving diodes; the Ga was in no danger.
 
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Hey there sba, don't sweat the small stuff, and always remember: BREATHE!!!

There will always be times when our perception does NOT agree with reality, and we scratch our heads, wondering;

"WTF??? This SHOULD'NT be happening. Am I seeing a shift in the laws of physics or something?"

And ONLY THEN, do we recognize our own boundless potential for stupidity.....and the "ah ha" moment arrives.

We all have those days. But, while we're on the subject of the laws of physics, there's this:


I remembered that when I was direct driving the diodes that they were only pulling 5.7V from the PSU!

Unless I'm mistaken (and please set me straight if I am), loads do not pull voltage. You see a voltage drop when forward-biasing a diode junction, but that diode is not pulling voltage.


Anyway, I hope your weekend allows you to decompress a bit. :)
 

Wolfman29

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They are rated for 20V, unless you're talking about the output cap - that's rated for 10V.
 
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Hey, Wolfman! Didn't expect you to answer here. In that case, I have several dead BenBoosts w/ caps galore on them. Do I need one that precisely matches the one on your driver, or can I just grab one of the same size and slap it in?
 

Sigurthr

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As long as the capacitance is the same as the original you can always replace a capacitor with another of the same composition (electrolytic, ceramic, etc) with one of a higher voltage rating.

example: a 350V 10uF electrolytic cap can replace a 6.3V 10uF electrolytic cap with no issue.
 

Wolfman29

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Indeed. I'll have to see a picture of what capacitor it is so I can tell you the capacitance needed.
 

Wolfman29

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Your picture doesn't work :\

EDIT never mind. See that you are using the CajunLasers pic.

From your description, I couldn't tell: is it the big one, the medium one, or the really small one?
 
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Wolfman29

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So that's just an input capacitor. Use 4.7uF and then as high a voltage you can get rating, at a minimum of 10V (assuming you are only using two Li-ions). The capacitors I use are rated for 20V (or was it 16V? It's saved on my cart order at mouser :p ).
 




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