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Banggood 405nm Laser Diode Replacement

Galactus

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May 24, 2020
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Hi, all! First post. I've scoured these forums, and I didn't really see anything like this (except a few post from several days ago, but didn't want to hijack the thread). I have a 405nm 500mw-ish Banggood laser module with a dead laser diode. I was burning something last night, and the laser quit working half way through the job. I tested the LD+ and LD- pads with a volt meter, and the voltage modulated while running a test burn. So I assume the board isn't the problem (well... more on that later). I snipped the diode leads, and there is no diodity in the diode. I'm assuming that IS a problem.

From what I gather looking at other posts, the driver can be an issue resulting in decreased diode life, but the posts stating that are several years old. I'm not sure if Banggood is even using the same board as when those posts were written. Looking at the drivers on DTR's page, they don't seem as complex as what is on mine, which is PWM. (I'll include a photo).

Second, I used this laser for PCBs (negative photoresist method), but the results were "OK", could be better. The divergence coming out of the diode significant. I even ordered a collimating lens, which gave a better quality dot, but there was always still a halo around the dot, which would partially expose stuff I didn't want exposed. I played with focusing, watched every video I could find, and still had problems. In the end, I would up making a cardboard cone that I fixed to the end of the module. That actually worked pretty good, but could have caused some heat issues that wound up killing the diode.

Which brings me to diode quality. I assume the ones Banggood are using are OK, and my expectations when I bought it were different than the reality. I just assumed that a laser diode would output a parallel, tight beam, and the lense would just focus it to a point. Boy was I wrong! In looking at replacements, the BDR-209 900mw 405nm in DTR's shop looks like a winner. 500mw is recommended for longest life, and my driver is 500mw. But how is the divergence?
Here's pics. The laser is the FB03-500 405nm PWM, and the driver is SW-LD62 v2.1.

Thanks!
 

Attachments

  • FireShot Capture 019 - Fb03-500 500mw 405nm blue violet laser module 2.54-3p ttl_pwm modulat_ ...png
    FireShot Capture 019 - Fb03-500 500mw 405nm blue violet laser module 2.54-3p ttl_pwm modulat_ ...png
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  • FireShot Capture 018 - Fb03-500 500mw 405nm blue violet laser module 2.54-3p ttl_pwm modulat_ ...png
    FireShot Capture 018 - Fb03-500 500mw 405nm blue violet laser module 2.54-3p ttl_pwm modulat_ ...png
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Last edited:





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...there is no diodity in the diode. I'm assuming that IS a problem.

While the presence of output voltage from the driver in the absence of light output does indeed suggest a faulty laser diode, the lack of... diodity does not. Most multimeters' diode test function cannot detect a forward voltage above a volt or two.
 

Encap

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THe BDR-209 is a 3.8mm diode what size is the Diode in the banggood unit 5.6mm or 3.8mm?

Might be a good time to upgrading to a better quality and higher output unit than the Banggood $40 device.
 
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Galactus

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It's a 3.8mm TO-18 package too. Seems like a perfect substitution. Trying to figure out the best way to get the old diode out now. It looks like there is just a brass tube inside the heat sink, but there is either striaght up rubber cement or rubberized thermal paste inside the sink too. Acetone does nothing to it. I may be able to hammer it out.
While the presence of output voltage from the driver in the absence of light output does indeed suggest a faulty laser diode, the lack of... diodity does not. Most multimeters' diode test function cannot detect a forward voltage above a volt or two.

Yeah, my regular volt meter has a continuity/diode function (which I call the "diodity" function...), but I also have a dedicated transistor/diode tester that does zeners up to 30v. Still nothing. Shows up as a 5.25 ohm resistor, nothing else.
 

sp5nzh

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Hi
Does anyone know the symbols of U1 and U3 systems.
Unfortunately, I connected the power supply backwards and now I'm trying to fix the module.
Regards Chris.
 

WizardG

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With regards to the 'diodity' of 405nm laser diodes: The reverse voltage which will kill the diode instantly is LOWER than the forward operating voltage. This makes them quite sensitive to static and ESD. It also makes a DMM quite useless unless the diode reads as a dead short.

And the divergence of all of the single mode 405 diodes is excellent.
 
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kecked

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Can’t read the chips. I’d test each diode and resistor. I suspect one of the resistors may actually be a Fuse.
the cops are likely an opamp of some flavor or a voltage regulator. The thing in the middle is an indicator. Looks like a 5.00 driver. Just Start over.
 





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