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1.8A driver not working

Hekken

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Recently I bought a new NDG7475 laser diode off of eBay along with a 1.8A SXD Super X-Drive Laser Driver M140 driver.
Once hooked up, the diode doesn't turn on, some times it does but the output is dim and goes out pretty fast. I returned the driver and bought a new one, which did a similar thing.
The driver is made for 7-12V input, here's my setup:

20210106_190418.jpg20210106_190356-min.jpg20210106_190408.jpg

The driver even produced a tiny bit of smoke.
I'm 100% sure all polarity is correct, there was no static either, I was grounded all the time. What could this be? Am I doing something wrong?
 



Unown (WILD)

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Looks to me you burned it out. It needs heatsinking as well as the diode module.
 

Giannis_TDM

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Looks to me you burned it out. It needs heatsinking as well as the diode module.
The statement of yours seems correct to me, Heard that they should be heatsinked well..... Although I do have one on my 465 and I have managed to overheat it only once ( the driver, not the LD, Heatsink for the LD is good enough) When I run it CW for about 5 min. I will replace it and compare it with one of my 3A bucks set to that. Ill replace it mainly for reverse pol protection
 

Hekken

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The statement of yours seems correct to me, Heard that they should be heatsinked well..... Although I do have one on my 465 and I have managed to overheat it only once ( the driver, not the LD, Heatsink for the LD is good enough) When I run it CW for about 5 min. I will replace it and compare it with one of my 3A bucks set to that. Ill replace it mainly for reverse pol protection
I only ran it for like 10 seconds at a time, should it burn out that quick?
 

Giannis_TDM

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I only ran it for like 10 seconds at a time, should it burn out that quick?
No, it shouldn't at all, Even my SDX which is in an enclosed space lasted 5min while powering a 7675 at 1.8A..
 

Encap

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If any clue/help for the OP, according to DTR who offers and sells them very sucessfully all day long:
"The Super X-Drive is an extremely efficient buck style regulator with many built in safety features to protect and give long life to your laser diodes. Driver has soft start, overshoot protection and very low noise. The driver can operate without an external heat sink with the current up to 1.5A , but it requires a heat sink for currents above 1.5A if you want continuous operation.
It works with 2 or 3 cells Li-Ion or 6.5V-12V DC PSU.
Don't power the driver without a load connected like connecting the driver directly to a DMM. If testing the driver remove laser diode and connect to a simulated load in series with a DMM to read the current setting or use what is commonly referred to as a "test load" which you can build a simple unit or there are some nice premade units with large sinked voltage drop diodes with selectable numbers of diodes. When connected to a laser diode a secure soldered connection between the laser driver and diode without anything else in series on the output of the driver."
From: https://www.ebay.com/itm/4-5A-SXD-S...058645?hash=item2a6babf7d5:g:sdcAAOSwzhVWsTO9
 
Last edited:

Giannis_TDM

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If any clue/help, according to DTR who offers and sells them very sucessfully all day long:
"The Super X-Drive is an extremely efficient buck style regulator with many built in safety features to protect and give long life to your laser diodes. Driver has soft start, overshoot protection and very low noise. The driver can operate without an external heat sink with the current up to 1.5A , but it requires a heat sink for currents above 1.5A if you want continuous operation.
It works with 2 or 3 cells Li-Ion or 6.5V-12V DC PSU.
Don't power the driver without a load connected like connecting the driver directly to a DMM. If testing the driver remove laser diode and connect to a simulated load in series with a DMM to read the current setting or use what is commonly referred to as a "test load" which you can build a simple unit or there are some nice premade units with large sinked voltage drop diodes with selectable numbers of diodes. When connected to a laser diode a secure soldered connection between the laser driver and diode without anything else in series on the output of the driver."
From: https://www.ebay.com/itm/4-5A-SXD-S...058645?hash=item2a6babf7d5:g:sdcAAOSwzhVWsTO9
I will do tests when I swap it out, Numbers are better than words, right? I didn't build a dedicated driver test jig for nothing!
 

Hekken

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Okay, so after some comments said it needed a heatsink, I added one and I even added a fan.
The diode turned on for maybe 3 seconds, but it turned dark after, I even cranked the current control down by a lot which should reduce the heat too.
(Sorry for the terrible image quality)
1610199726845.png
 

Encap

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So are you saying the diode is NG/has gone LED, either before you received it or after for whatever reasons and the second driver is still OK, perhaps?

Even if you somehow ruined the first driver, what are the chances and new second driver would arrive unused and also runied.
Simplest explaination for what you are seeing on the surface of it is that the diode is bad/ has been LED'd.
From what you say the driver works as you were able to adjust the output assuming you measured the output and not just a guess arbitrarily turning a pot down anyway, it did light the diode dimly which sounds like bad/LED'd diode for a few seconds.
If that is the case you could go through 1/2 doz. drivers or however many and the result would be the same.

I don't see any diode test info in your posts.. Have you tested the diode without the driver to see if it is working/lasing or burned out now LEDing and producing dim light for a moment or two?
You could set your PSU to supply Current not Voltage output if it has that feature and adjust to the one of the settings, your choice, in the diode test photos you see when you scroll down on the NDG7475 page on DTR's web site and see if it is or is not the problem. see: https://sites.google.com/site/dtrslasershop/home/diodes/ndg-1w-520nm

Anyway good luck --maybe next time buy the assembled module with diode, driver and lens which is tested and working fine before it is shipped.
 
Last edited:

Giannis_TDM

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So are you saying the diode is NG/has gone LED, either before you received it or after for whatever reasons and the second driver is still OK, perhaps?

Even if you somehow ruined the first driver. What are than chances and new second driver would arrive unused and also runied.
Simplest explaination for what you are seeing on the surface of it is that the diode is bad/ has been LED'd.
From what you say the driver works as you were able to adjust the output assuming you measured the output and not just a guess arbitrarily turning a pot down anyway, it did light the diode dimly which sounds like bad/LED'd diode for a few seconds.
If that is the case you could go through 1/2 doz. drivers or however many and the result would be the same.

I don't see any diode test info in your posts.. Have you tested the diode without the driver to see if it is working/lasing or burned out now LEDing and producing dim light for a moment or two?
You could set your PSU to supply Current not Voltage output it it will do that and adjust to the one of the settings, your choice, in the diode test photo you see when you scroll down on the NDG77475 page on DTR's web site and see if it is or is not the problem. see: https://sites.google.com/site/dtrslasershop/home/diodes/ndg-1w-520nm

Anyway good luck --maybe next time buy the assembled module with diode, driver and lens which is tested and working fine before it is shipped.
I think he tried to current limit the source to the driver, The SDX is a set driver, meaning no potentiometer.
And it's apparent by his PSU too. OP FYI current limiting the source to the driver may cause issues in some drivers and even kill them. Set your PSU to 8,4v and turn off current limiting, See if that works for ya.
 

Giannis_TDM

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Okay, so after some comments said it needed a heatsink, I added one and I even added a fan.
The diode turned on for maybe 3 seconds, but it turned dark after, I even cranked the current control down by a lot which should reduce the heat too.
(Sorry for the terrible image quality)
View attachment 71205
Please solder the diode directly to the driver for 2 reasons: The long ass wires you have there may pick up trash and knock the drivers feedback out and that those wires are tiny causing a lot of voltage drop across them, Solder the diode directly and solder thicker wires to the input.
 

Wakrah

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I had a similar problem due to trying to use long leads like that some years ago, too much voltage drop, but my leads had very small diameter wires in them, that's why I had so much voltage drop. That said, if you push the current to 1.8 amps, I would think the diode should lase, you would just need to have a much higher voltage than normal at the power supply output terminals so enough would be at the diode leads, due to the voltage drop, if that is the problem. Also, some diodes go dim if you over current them, but can recover, if you don't do so too long or over heat the diode. Just some ideas, don't know what else to suggest. Make sure you are setting the current limit.
 




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