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Laser death

m3vuv

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Hi all,ive been playing with a m140 2watt nichia 450nm ld,last night i tried to crank the driver power up to 1800mw,i got to 1600mw and decided to test it,it powered on for about 2 seconds and died,it now looks like a dim led,i heard these are supposed to take up to 2amps input power?,the seller i got it from sells 1.6 watt diodes to,just wondering if this is normal or more than likley was i sold a 1.6 watt by mistake?,cheers m3vuv.
 

m3vuv

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I am looking at buying a nichia nubmo8 4.75 watt ld,it comes with a ball lense,can i use this with a g2 lens assy,any ideas,cheers paul m3vuv.
 

GSS

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You can use it with a G2 although there is good evidence that removing the Gball lens will cause early diode failure..
 

m3vuv

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is it still possible to focus these to a spot maybe 3 inches away using a g2 lense with the original still in place for engraving?
 

GSS

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Maby member RedCowBoy will chime in, he's the master lens guy:)
 

RedCowboy

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I'm no expert, just an enthusiast. :)

If you remove the GBall and use a G2 your divergence will be as bad as a nubm44 and your diode will have a shorter mean time to half brightness.

Why not just use a nubm44 ?

Answering my own question the 08 is 450-455nm compared to 445-450 so that's a small reason, I much prefer the nubm44.
 
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Lifetime17

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Hi, At 1.8A the A140 diode will do 1600mW's . Look in-between the POS+ and NEG- pins and see if there is a square bar code. This will indicate that it is a M140. No Bar code is a A140 ... So you can tell if the vendor is selling The a"a for M140's. both can be ran at 1.8A .
A140 + 1,600 + / M140's + 2+ W'sat 1.8a / G2 lens. the divergence is nice of the two diodes.

Rich:)
 

m3vuv

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yup it has a circle and barcode etc so looks like its gen,anyway the seller has said he will send a replacement if i stump postage,im ok with that,looks like ihad a duff one maybe,i was measuring the current with my fluke in series with it as opposed measuring volt drop across a diode string and resistor i thought it would be more accurate with tolerances of resistors etc.
 

Lifetime17

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Hi, You have to remember that a lot of these pulls are from projectors with many hours on them . And the vendors that sell them don't realize or just don't care about total hour usage on the machines. a lot of used machines have many hours on them and are cheap to harvest the M's and A140's and sell them not binned. So basically it's luck to get an efficient diode from these projectors.

Rich:)
 

m3vuv

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yes i suppose its pot luck,any idea what projectors use them so i can search on ebay for non working ones?
 

paul1598419

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I would not adjust the current on a driver connected to a laser diode. The noise from the pot can cause the diode to fail. You would get better results from a dummy load as the pot can't harm that.
 

m3vuv

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would it not be ok with say a 10uf cap accross it while adjusting to absorb any spikes?
 

paul1598419

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I wouldn't. It is up to you to decide if it is worth taking the risk.
 

m3vuv

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very true,i may use the fried one as a dummy load as it still draws plenty of current,set it then fit the new one
 




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