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Thread: Simpledrive (5) issues.

  1. #11
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    In this case, you should read no more than 4V@1.8A and 4.5V@3.5A on the diode. At least I have not seen these diodes with another V-A curve
    The cables from PSU to driver are beefy, the ones from driver to diode are rated for 3A.
    Do you use anything like lasorb and how is it connected, if so?

  2. #12
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    Quote Originally Posted by Bbe View Post
    Do you use anything like lasorb and how is it connected, if so?
    Oh, right.
    Lasorb is glued to the top of the diode brass housing. Very short cable goes from the diodes anode to laserb's and the same for the cathode.

  3. #13
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    This thread just piqued my curiosity....Click image for larger version. 

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ID:	51900 I am just as surprised as Bbe by these measurements.
    Could you re-check them and confirm that LD is really a NUBMO7E
    Cheers
    Have you got a scope to see if your supply is really giving a solid DC voltage/current rather than a ragged high frequency AC wobble with a DC bias ?
    Something is definitely not kosher here !
    Last edited by catalanjo; 03-17-2017 at 15:27.

  4. #14
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    No scope I'm afraid.

    This is weird, with another Simpledrive 3 and a red mitsubishi 500mW diode I notice power peak at 650mW.
    With both the red and blue at the same power output the voltage and current is higher than what DTR has on his website photos and the power drop for mitsu begins at 650mW (which is at 2.8V) and for NUBM07E at 3.1W (which is at 4.9V, 2.6A current).
    Oh and sorry, it was 4.9V, not 6.9.

    I just noticed, after a while the power cable from driver to diode gets warm. THat could explain i8t for the blue.
    But don't experience that for the red.

  5. #15
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    @ "Oh and sorry, it was 4.9V, not 6.9."
    Aha ......... I think Vlad will sleep better now!
    This is obviously NOT a simple drive issue.
    Also looks like your multi-meter is consistently measuring slightly high voltages, what make of meter is it and have you checked it against a known voltages (eg 7805 or 7812 regulator chips, known zenerdiode or a USB supply on a computer)?
    Cheers
    PS. When wires get warm it is usually a good time to start using bigger section wiring ...thermal runaway in wires makes a very nasty smell, if you want to limit the current ,much better to use a sealed fuse !

  6. #16
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    Thicker wire than the one I use is just hard to solder to a tiny diode pin, but I'll manage it. Anyway, this is only an issue with the blue diodes, not the reds.

    I replaced the multimeter's battery, and I can try with another one. But a faulty multimeter wouldn't explain why I'm getting a much lower laser power reading with a Laserbee AXA before the peak is reached and the power actually decreases.

  7. #17
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    5.9...6.9...4.9! If you can confirm the last measurements, then we can go ahead ))

    So, you said that you can not go higher 1.8A with the driver, but your measurements suggest the opposite. 4.9V on NUBM07 means that the operating current at this point is higher than 3.5 - 4A. This is an obvious fact that can be questioned only if your diode is defective or damaged. Why you can't get the expected optical power? I see several possible reasons:
    1. Defective diode or defective/incompatible optics
    2. Defective or incompatible lasorb - it can absorb some of the power from the electrical circuit
    3. Laserbee is not an industrial power meter, I would not trust the measurments results unconditionally.

    issues, 5 pcs
    This is obviously NOT a simple drive issue.
    Last edited by Bbe; 03-20-2017 at 04:01.

  8. #18
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    Quote Originally Posted by Bbe View Post
    confirm the last measurements, then we can go ahead ))
    confirmed

    1. Defective diode or defective/incompatible optics
    This would mean defective red and blue and green diodes, I think low likelyhood.

    2. Defective or incompatible lasorb - it can absorb some of the power from the electrical circuit
    Same here, each diode has its own lasorb from lasershowparts.

    3. Laserbee is not an industrial power meter, I would not trust the measurments results unconditionally.
    At 3.5-4A the blue diode would produce a 4.4-4.8W power.
    A 1W+ difference in reading would be very surprising.

    I sure hope this is a multimeter thing. I'll try with another one.
    Or maybe the lasorbs arent correctly connected. Anode to anode (marked with an "A" on the lasorb) and cathode ti cathode right?

    I can also try swapping the g2 lens with a 3element lens.

  9. #19
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    First you need to measure the operating current in the anode or DC+ circuit break. By circumstantial evidence (voltage drop on the diode) it's about 4A.

    What do you think about it? Is it possible at 1.8A?
    The cables from PSU to driver are beefy, the ones from driver to diode are rated for 3A.
    I just noticed, after a while the power cable from driver to diode gets warm.

  10. #20
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    Quote Originally Posted by Bbe View Post
    What do you think about it? Is it possible at 1.8A?
    Think about what? (Sorry)

    I measured the red again today with someone else's multimeter. It doesn't seem to be the multimeter's fault.
    This is the result:

    Peaks at 2.66V, 1.6A, 640mW laser output.
    Tried with 3element glass lenses, it doesn't seem to be the fault of a bad g2 lens.
    Interesting fact: the diode housing doesn't get even slightly warm.
    Power cable from driver to diode is 22AWG, 40cm in length, cable doesn't get warm either (unlike for the blue).

    Tested the laser power meter with my old 200mW DPPS module, shows correct results. And the red beam isn't burning my hand so I'd assume it's really not higher than 650mW.

    Does the diode housing not warming up hint anything? What about the cable AWG?

    Maybe everything is fine and I'm doing something stupid with the bias pot?

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