445nm Laser is bright at first then dims.

grainde said:

I once had a dodgy diode that did exactly the same thing. It would power up brightly for a fraction of a second and then go dim and this every time I turned it on. The diode was being run at 1.8 A and would get hot very quickly. I spoke at length to DTR about it, but we never found out why it was behaving that way. In the end I had to buy a new diode.

I can post a vid if you like for comparative purposes?:beer:

Edit: There were no shorts on the driver and at least two drivers at different currents were tried. Do you have a different driver to test?

Click to expand...

this is my first build, i dont have a different driver to test. and i doubt its faulty because lazz tests his drivers before he sends them out. it does heat up very quickly!

http://www.youtube.com/watch?v=60o1ZXiiBRU <------------------- Video of laser dimming

Blord said:

Is that a bench PSU in your video ? If you can set the current you can direct drive the diode for testing purposes. Just eliminate the factors that cause the problem.

A normal M140 diode can handle the 1.8A current without problem. They are dimming when the current is push much higher.
Sometimes the diode is a dude. They reach the maximum current at much lower level like 1A and when you push the current there is no gain.
At 1.8A it could be dimming.
I think you have a dude diode.

Lazeerer always checked the drivers he sells. So a faulty driver is very rare.

Click to expand...

i cant set the current with my PSU, its rather old. and i agree with you on lazeerer's driver. i highly doubt its that


judging by the grainde's experience, im pretty sure the problem is the diode. sucks to buy a faulty diode (potentially!) :cryyy:

where the hell does the term "dude" come from?

supadots said:

this is my first build, i dont have a different driver to test. and i doubt its faulty because lazz tests his drivers before he sends them out. it does heat up very quickly!


judging by the grainde's experience, im pretty sure the problem is the diode. sucks to buy a faulty diode (potentially!) :cryyy:

Click to expand...

There are several possibilities, other than a dud though. So you should rule those out first:

Did you discharge the caps on the driver before connecting up the diode?
Did you take electrostatic precautions?
Are you sure you didnt exceed your 1.8 A?
Did you keep soldering time to a minimum ie less than 1 sec per pin?

If the answers to these questions were yes then it is possible. If however any are no then they could be the cause.

As I mentioned we never found out why my diode behaved the way it did, but Id really like to know why...Maybe you could get yours removed from the module and decanned, should it be consigned to the graveyard...?

supadots said:

where the hell does the term "dude" come from?

Click to expand...

Dude is a guy...dud is a dead or non-functioning piece of equipment, usually a military term used for shells and such...

grainde said:

There are several possibilities, other than a dud though. So you should rule those out first:

Did you discharge the caps on the driver before connecting up the diode?
Did you take electrostatic precautions?
Are you sure you didnt exceed your 1.8 A?
Did you keep soldering time to a minimum ie less than 1 sec per pin?

If the answers to these questions were yes then it is possible. If however any are no then they could be the cause.

As I mentioned we never found out why my diode behaved the way it did, but Id really like to know why...Maybe you could get yours removed from the module and decanned, should it be consigned to the graveyard...?




Dude is a guy...dud is a dead or non-functioning piece of equipment, usually a military term used for shells and such...

Click to expand...

well they are saying dude, not dud. its throwing me off.

Did you discharge the caps on the driver before connecting up the diode?
yes sir, even though i have no idea if it worked or not.

Did you take electrostatic precautions?
nope. pretty sure everything was in one of those special anti static bags.

Are you sure you didnt exceed your 1.8 A?
exceed current? not too sure how i could do that.. yes.

Did you keep soldering time to a minimum ie less than 1 sec per pin?
yes.

supadots said:

Did you discharge the caps on the driver before connecting up the diode?
yes sir, even though i have no idea if it worked or not.

Click to expand...

If you touched the output leads together it should have been fine.

supadots said:

Did you take electrostatic precautions?
nope. pretty sure everything was in one of those special anti static bags.

Click to expand...

That's true, but once you remove the diode from the packaging its no longer protected. You should ground yourself before removing and touching the diode...:undecided:

supadots said:

Are you sure you didnt exceed your 1.8 A?
exceed current? not too sure how i could do that.. yes.

Click to expand...

Well did you try anything else, other than the driver, to run the diode?

supadots said:

Did you keep soldering time to a minimum ie less than 1 sec per pin?
yes.

Click to expand...

Not really relevant as the diode was supplied with leads attached...:beer:

grainde said:

If you touched the output leads together it should have been fine.



That's true, but once you remove the diode from the packaging its no longer protected. You should ground yourself before removing and touching the diode...:undecided:



Well did you try anything else, other than the driver, to run the diode?



Not really relevant as the diode was supplied with leads attached...:beer:

Click to expand...

Well did you try anything else, other than the driver, to run the diode?
nope.

That's true, but once you remove the diode from the packaging its no longer protected. You should ground yourself before removing and touching the diode...:undecided:
i never touched the diode itself. and i never discharged myself on the diode. i highly doubt i killed the diode like this.

Not really relevant as the diode was supplied with leads attached...:beer:
i was talking about when soldering to the driver. but i see what you meant now.


anyways, is it the most likely the diode? regardless as to if i'm the reason the diode is a dud or not.

supadots said:

anyways, is it the most likely the diode? regardless as to if i'm the reason the diode is a dud or not.

Click to expand...

It is possible yes, but I guess you'll have to wait and see what DTR says? :thinking:

In any case I was unable to remove my diode from the module as I was using a GB module, where you couldnt access the base of the diode from the front. If you have one of DTR's modules however, it should be possible to remove it and do an autopsy. That is, if you wanted to? :beer:

grainde said:

It is possible yes, but I guess you'll have to wait and see what DTR says? :thinking:

In any case I was unable to remove my diode from the module as I was using a GB module, where you couldnt access the base of the diode from the front. If you have one of DTR's modules however, it should be possible to remove it and do an autopsy. That is, if you wanted to? :beer:

Click to expand...

well if it was the diode, i would send the unit to DTR for him to put it in, because i have none of the tools to do so. (not implying he gives me a free replacement, i can pay if he needs me to, because, sh*t happens.)

On your video the driver is clearly not regulating. It is drawing more current as the voltage goes up. It should do the exact opposite. Look like it is basically direct driving the diode with the dropout of the regulator figured in. The driver for whatever reason is not regulating.:beer:

One thing about diodes. If they laser for a few seconds they work. Any issue would then be power or heat related.

And for the other questions yes every diode is tested before being shipped.

I would stop running the diode till you can get the driver tested as it could become damaged if it keeps dimming from over current.

What appears it is that you have somehow shorted GND to LD-.

The Driver will not fail in this case but you are by passing the regulation.

THe Only Place that this can happen on the driver is if you have LD- Pad shorted to the cap behind it. Not the side DTR showed but the LD- side.

Also the second place it can happen is on the back of the diode. Make sure you do not have your case pin shorted to LD-.?
or
Dropped a solder ball down on the back of your diode that is shorting LD- to the case.
or
The diode insulation is not damaged on the LD- pin.

There is No where on the driver that can be short before i ship out so it has to be one of those places that happened when soldering.

Also check for a bridge across the R4 and R5 if you got any solder on there.

But for sure the issue is you have LD- shorted to GND.

If this happens at 6V then your diode will receive ~2A. At 6.5V it will get ~ 2.5A and at 7V ~2.8A.

So get a test load setup and test it on there.

Or maybe its something as simple as you shorted the Diode Case pin to the LD- pin as i see a third wire coming out the back of your diode but cant tell if its connected to anything.

If you are not comfortable to do this then send it over to me and ill see where its at and fix it.:beer:

Lazeerer has a point. I recentally thought that a driver
I was using had Ld- and Gnd as the same. I hooked the
power up that way and it bypassed the current sense resistor.
That poor diode tried to warn me three times - then died.
HMike

DTR said:

On your video the driver is clearly not regulating. It is drawing more current as the voltage goes up. It should do the exact opposite. Look like it is basically direct driving the diode with the dropout of the regulator figured in. The driver for whatever reason is not regulating.:beer:

One thing about diodes. If they laser for a few seconds they work. Any issue would then be power or heat related.

And for the other questions yes every diode is tested before being shipped.

I would stop running the diode till you can get the driver tested as it could become damaged if it keeps dimming from over current.

Click to expand...

DTR is correct. its not the diode

lazeerer is correct. its not the driver.

something has to be shorted. im going to search for it.

EDIT: nope.

i cant find any shorts. nothing, not a single spec of solder anywhere. what.

The only way to know is test the each part separate. Use a testload for the driver and for the diode the bench PSU.

If you want send the diode and driver to me and ill look at it and fix the issue. The Short is somewhere.

Also there could be a chance that you have cleaned away the short but now the driver is damaged.

Wont cost you anything but a couple of dollars to ship it to me.

Because looking at your pictures i cannot see anything .

lazeerer said:

If you want send the diode and driver to me and ill look at it and fix the issue. The Short is somewhere.

Also there could be a chance that you have cleaned away the short but now the driver is damaged.

Wont cost you anything but a couple of dollars to ship it to me.

Because looking at your pictures i cannot see anything .

Click to expand...

http://i.imgur.com/7XQQNtT.jpg <----- super high res
http://i.imgur.com/ee6RuOy.jpg <--------- the tiny glob of solder on the C1 wasnt there before the problem started occuring, i just did that a couple min ago resoldering the leads.

that's what im going to have to do (send it to you). can you PM me your address mr. lazeerer?

Yeap.

Even with your High Res Pic there is Nothing to see. Ill Physical have to test everything to find out what happened to fix it.

Should only take me 5 minutes.

THe short might of happened at first then got cleaned up and now the driver is damaged.

if thats the case ill replace whatever is needed and wire everything back up for you no charge.

Ill be able to tell if and how and where the short happend and ill post the results here.