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Question - M140 weak. damaged?

Z

Zergee

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Hello!
Sorry for the new thread, can't really find any place to ask.
I bought an M140 445nm Laser (DTR, ebay) a year ago, i only had the chance to install/try it today. I also bought a TTL driver for it from x-wossee (SD1x3A (r07)).
Wired it up okay(using arduino+ramps on a CNC build), did it by the attached guide.
First i turned bias and gain down, then turned bias CW until it turned on. Then while measuring current inline, turned gain up.
However, at about ~0.5A, the MOSFET on the driver became pretty hot (70°C+).
At the power, i could engrave wood, and cut paper (had to play a lot with focus).
So problem is, i turned it on again a few minutes later, changed nothing, and now it didn't even engrave, or burned wood/paper. another restart, and the laser is really dim, but driver takes the same current, MOSFET gets really hot also.

Did i damage the laser somehow(had heatsink and fan, only got slightly warm), or could the MOSFET be damaged and still run the a laser at a reduced power?

Measured the voltage to the laser from the driver, 4.17V.

WOuld appreciate any help, thanks! :)
 





Just measured Current from driver to diode. ~1.1A. Laser is still dim.
Guess i damaged it somehow?:thinking:
 
Out of curiosity, how high did you take the current when it worked?

The diode is probably toasted if it's getting 1.1A and dim though.
 
Rivem said:
Out of curiosity, how high did you take the current when it worked?

The diode is probably toasted if it's getting 1.1A and dim though.
Click to expand...

1.1A was the max, didn't touch it since it dimmed.
I just can't really figure out what happened with it..
 
Weird things can happen with low-quality and even some decent drivers. Might just want to look for a better one next time and use a test load to adjust before you hook it up to your diode.
 
This is good advice from Rivem.

if you have a adjustable bench power supply you could test the laser diode with that, set the voltage to around 3.8-4.2 volts and see what current is being drawn by the LD,
if it's not already 1100mA then turn the voltage up slowly until you reach 700mA the LD should be putting out around 800mW at that current, good luck ;)


Rivem said:
Weird things can happen with low-quality and even some decent drivers. Might just want to look for a better one next time and use a test load to adjust before you hook it up to your diode.
Click to expand...
 
Nah, it has the same brightness as an LED, so it's definitely dead..

Could you recommend a reliable laser for engraving wood/cutting paper maybe, with a driver? If it's not too much to ask :)
 
Flaminpyro said:
This is good advice from Rivem.

if you have a adjustable bench power supply you could test the laser diode with that, set the voltage to around 3.8-4.2 volts and see what current is being drawn by the LD,
if it's not already 1100mA then turn the voltage up slowly until you reach 700mA the LD should be putting out around 800mW at that current, good luck ;)
Click to expand...

correct me if I'm wrong but shouldnt you limit the current instead of the voltage when hooking up the diode to a PSU? That's how I test my diodes with my DC PSU, by turning the voltage knobs all the way up and the current knobs all the way down, then slowly turning up the current knob until I get to the desired Amperage.
 
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