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ArcticMyst Security by Avery

Blowing diodes left and right

bobo99

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May 18, 2011
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Hey guys, so still working on my first build and well, still trying to learn the ropes... by blowing up some diodes :cryyy: (and head banging smiley)

Working on a 405 (S06J) - V5 flex drive build with one 18650.

My process was as follows:

1) Bought a completed test load from Jufran88. Great little thing. Set the jumper to 6, for 6 diodes to simulate the blu ray diode.

2) Set the current to 520mA. I know this is a little higher, however there was this weird spot where there was a gaping hole between 480-520mA. Now at this point I turn the battery off, then on, then off then on, and make sure it ALWAYS hits 520, and it does, like a rock, no overshoot, just straight to my desired current setting.

3) TESTED the diode and it worked great. Even burned a nice little hole in my wall 10 feet away. OK super. Total run time of about 20 seconds, pretty strong, no fluctuations, nothing.

4) Mixed up some thermal adhesive and glued it in my custom host. Let it set for about an hour. Checked the current output again! Good - shorted the leads on the driver with a resistor.

Hooked up all the wires, and pressed the magic button, BRIGHT light for 1 second, and then this faint light that I can't even see through my goggles.
F&*^

So the first thing I think of is ok clearly current is WAYY too much, but 520 doesn't seem like it would just KILL it. Then again I have no idea what too much would be.

So unsolder all the wires, hook it back up to the test load, and there it is, it hits 800, down to 600, then hovers around 650 (mA) then continues to oscillate up and down between 600 and 800.. I sit there with it, and say smarten up. I then turn it down to 480mA and then its rock solid again, no overshoot no oscillation nothing. The driver is properly heat sinked with the thermal adhesive, so I don't think thats the issue.

Clearly the diode is toast, (my second one :( ) but what could have gone wrong?

The only thing that could of happened was when I was stuffing in the wires, that somehow the pot got turned, almost 1 full revolution :S? A act of proverbial god, the pot is hard enough to turn when your trying..

I had my friend make this custom on a lathe, so heatsinking IMO is not an issue, probably overkill.

Any words of advice? Other than 3rd times the charm?

EDIT: Positive pin is hooked up to positive driver lead, and the negative and case pin are hooked up to the negative of the driver output.
 

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If the pot got turned once you set it to the desired output put a little glue on it so it can't move
 

bobo99

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Agreed, will get done next time. However why was the output oscillating so much after the assembly? What would cause that ? Currently at the 480 setting it always goes to 480, no oscillations...

Is it the on 18650 not being able to provide enough current at 750mA and the boosting voltage? Just would like to understand why the driver behaved the way it did ( assuming the pot was turned)
 

Blord

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The Microflex are good drivers. They are very stable with alot of safety features.
You made a short circuit somewhere. The Artic Silver is to blame I think. It is good for heatsinking but it also conduct electricity and that is not so good for a driver.
Use the white ceramic version of that.
 
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bobo99

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I made SURE to only put the arctic silver around the axis housing and between the heatsink. For flexdrive mounting I used the Arctic Thermal ADHESIVE...

Now in their data sheet they say its "slightly" capacitive (adhesive), and that it shouldn't be used on small pins and traces, etc, which is what I did. But I've seen plenty of builds on here that have used that method....
 
Joined
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Sorry to hear of your misfortune. Hey, it's part of the learning process.
I do not even want to think of how much money I have seen go poof in the form of laser diodes. :(

I'd suggest using some glue on the pot like mentioned above.

I use the Arctic Silver adhesive on my drivers as well; I've never had shorting isssues due to the adhesive itself.
I always use a DMM and check for continuity between the sink and the leads before final assembly.

I have had Flex's that acted erratically, so I could possibly be a defective driver as well.

Good luck! Hopefully the third time is a charm for you. :beer:
 

DTR

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I would certainly check to see that the driver was not shorted anywhere. Also you will not need to sink the driver running just 500mA. Just wrap it in electrical tape and you will be good.:beer:

I do suggest 500mA as a max. Some people do run them a lot higher without immediate issues but it is expected to have a shorter life expectancy.
 
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rhd

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I've said this before, and I know MANY disagree, but I'd just stay away from the Flex / Microboost drivers.

I think they're sketchy and have poor QC and support. All the lava drivers I've encountered in the last 6 months have had issues. The only Lava driver that I think is rock solid is the Groove.

Try a linear driver. It's less efficient, but you'll never have to second guess the safety/reliability of a driver you make yourself.
 
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really rhd i have never heard that before....:thinking:

it doesn't matter to me because i don't use them...but i thought the reason they where $25 was because of how fantastic they are claimed to be...

this could turn into a very interesting issue if it continues

thanks for bringing this concern to light
 

rhd

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really rhd i have never heard that before....:thinking:

it doesn't matter to me because i don't use them...but i thought the reason they where $25 was because of how fantastic they are claimed to be...

this could turn into a very interesting issue if it continues

thanks for bringing this concern to light

I'm certainly in the minority on this one - and I know it. You'll find a lot more people around here that love them to death, than agree with me.
 
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I'm certainly in the minority on this one - and I know it. You'll find a lot more people around here that love them to death, than agree with me.

yep well if they continue malfunctioning you wont be the only one complaining. i guess we shall see:undecided:
 

bobo99

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Well, I will leave this driver in, and DTR was kind enough to send me a new diode.

So. tests to preform,

1) 480mA, will take a video so you can all verify
2) Continuity test, make sure driver isn't shorting out on the heatsink
3) Glue the pot down

Next build will be with a Jib linear driver, so I guess less that can go wrong with that one..?

@DTR thanks- however the datasheet for the flex drive says at 500mA and above it requires heatsinking, and I tried grabbing this thing at 500mA and its too hot to touch!!

Thanks for the feedback all, hopefully will be able to put up a "real" first build thread soon :)

Edit: well already failed the continuity test between the heatsink, and the driver output...(something I will always check for from now on). Now to figure out how to remove this cement somehow..
 
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Why not try turning it down a bit, run it at 400mW for a while and if you just can't
stand it any longer turn it up then, it'll give you something to do later :crackup:
 
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Joined
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Well, I will leave this driver in, and DTR was kind enough to send me a new diode.

So. tests to preform,

1) 480mA, will take a video so you can all verify
2) Continuity test, make sure driver isn't shorting out on the heatsink
3) Glue the pot down

Next build will be with a Jib linear driver, so I guess less that can go wrong with that one..?

@DTR thanks- however the datasheet for the flex drive says at 500mA and above it requires heatsinking, and I tried grabbing this thing at 500mA and its too hot to touch!!

Thanks for the feedback all, hopefully will be able to put up a "real" first build thread soon :)

Edit: well already failed the continuity test between the heatsink, and the driver output...(something I will always check for from now on). Now to figure out how to remove this cement somehow..

Good luck on removing the adhesive. It usually breaks off the top of the inductor.
I usually get a small screwdriver and *carefully* pry the driver up.
The adhesive usually lets loose on the smooth heatsink side.
Then re-attach, making sure you have enough adhesive to give a thick buffer to avoid shorting.

As far as heatsinking goes, I heatsink no matter what.
That way, I'm safe. More heatsinking wont hurt, but a lack of sinking will.

Just my .02. :cool:

Edit: Oh yea; If you are using a Jib driver next, be cautious when adhering it to the heatsink.
The resistors on the backside have a tendency to short out on the sink.
I try to use a thick amount of Arctic Silver epoxy and hold it away slightly until the adhesive sets.
Then test continuity. :beer:
 
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DTR

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I've said this before, and I know MANY disagree, but I'd just stay away from the Flex / Microboost drivers.

I think they're sketchy and have poor QC and support. All the lava drivers I've encountered in the last 6 months have had issues. The only Lava driver that I think is rock solid is the Groove.

Try a linear driver. It's less efficient, but you'll never have to second guess the safety/reliability of a driver you make yourself.


What kinds of stuff have you been seeing?



@DTR thanks- however the datasheet for the flex drive says at 500mA and above it requires heatsinking, and I tried grabbing this thing at 500mA and its too hot to touch!!


It should not get that hot. I just ran a 445 set to 1.15A and it took almost 40 seconds before I had to stop pinching it with my finger and I continued the run up to 2 minutes and the driver did not overheat. If your driver is burning hot in seconds I am thinking there is an issue with he driver.

Good luck on removing the adhesive. It usually breaks off the top of the inductor.
I usually get a small screwdriver and *carefully* pry the driver up.

I have used a razor blade with good success in the past.:beer:
 
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The title of this thread made me laugh. A lot. That is all. (Sucks about the diodes though)
 




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