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Thread: Viasho 1W 532 PSU question?

  1. #11
    Join Date
    Jan 2007
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    Sheepsville, Wales, UK
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    3,406

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    Just to calrify what Jim is saying....

    When I first got the laser the diode current value I measured was above the readings I was getting on the front panel meter. So although this was only indicating up to 4.3A it was actually pumping the diode current towards 5A! So when we replaced the diode the first thing I did was find out which pot on the driver board (internal) actually set the max that the driver will supply. I have marked the pot on the attached image. I tested the current using two different methods, one with an ammeter in series with the diode feed and the other with a voltmeter across the diode ballast resistors. These are 4x 0.33 ohm resistors in parallel so their combined resistance is 0.825 ohms. Calculating the current using the voltages I was getting on my meter across these confimed that the front panel meter was way out. I set the current so it would max out at 4.3 amps and the front panel meter read 3.85A
    After realigning the laser and getting it back to spec I adusted the front panel meter calibration pot (also shown on the atached image) so that the display agrees with my measurments. Testing the readings throughout the range I am confident that the meter on the front is now accurate.
    It is my considered opinion that this inaccuracy of the front panel meter was the reason this laser croaked as it appeared it was only being driven to its max current when it was in fact being driven beyond this value.

    Viasho owners I would measure your diode current if I were you! Simply measure the voltage across the ballast resitors (four in a row on the image just to the right of the green connector block on the top edge) and use ohms law to determine the actual current.

    Rob
    Attached Thumbnails Attached Thumbnails viasho.jpg  

    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
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  2. #12
    Join Date
    Mar 2008
    Location
    Canton, GA USA
    Posts
    384

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    Hi Rob,

    I think you meant 0.0825 ohm for 4x .33 in parallel...

    Tim

  3. #13
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    Jan 2007
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    Sheepsville, Wales, UK
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    I think you are right - My typo

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  4. #14
    Join Date
    May 2006
    Location
    Norway, Fauske
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    1,206

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    This was interessting reading. I will check my 1.5watt laser when I can...

  5. #15
    Join Date
    Jan 2008
    Location
    South Lincs, UK
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    2,625

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    Just a couple of pictures of the laser head assembly internals for you all to peruse over:
    Attached Thumbnails Attached Thumbnails IMGP1665.JPG  

    IMGP1667.JPG  

    --------------------
    My Brain urt's!

    Continuously in Awe! of (H)Al, the Photonlexicon Font of Complete Knowledge - The (H)Al'PL Database of complete puss that no one needs to know or ever trusts as he ain't really got a Scooby doo about now't!

  6. #16
    Join Date
    Dec 2006
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    Scotland
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    comments please frank
    In the beginning there was none. Then came the light - #1 UKLEM - 2007
    BUY UK LEGAL LASER POINTER :: NEW - Blue 460nm Laser Pointers

  7. #17
    Join Date
    Jan 2008
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    South Lincs, UK
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    I guessed there would be no reply.
    --------------------
    My Brain urt's!

    Continuously in Awe! of (H)Al, the Photonlexicon Font of Complete Knowledge - The (H)Al'PL Database of complete puss that no one needs to know or ever trusts as he ain't really got a Scooby doo about now't!

  8. #18
    Join Date
    Nov 2007
    Location
    Southampton, UK
    Posts
    458

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    Just want to say thanks for this useful thread, and especially to Stanwax for his detailed explanation as to how to check the output current. I have one of the 1W Viasho green modules from last year's group buy - however, it has only been run for a few minutes on full power as it's awaiting installation in my upcoming RGB projector. I shall certainly be delving into the PSU with my voltmeter before I run it again, prevention clearly being better - and cheaper - than cure. I'm surprised that Frank hasn't replied to this, he must realise that Viasho could lose business if he fails to keep his customers happy; perhaps Viasho's recent introduction of a new power supply is tacit admission that there was room for improvement in the previous design...

  9. #19
    Join Date
    Mar 2007
    Location
    Rotorua New Zealand
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    528

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    Mine did a similar thing. Had to go back to China. Its a 1.7watt version.
    They did fix it under warranty though with some input from Dave at LaserShow parts riding their case.
    They don't like to talk about "faults" in some of these Asian countries.
    Cheers
    Ray

  10. #20
    Join Date
    Jul 2009
    Location
    China
    Posts
    35

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    Hello everybody, I am new here, got no idea what happens if I reply this obsoleted topic.

    I am from China, I met Frank days ago. I was thinking to buy a 1w from viasho for building new RGB, this thread almost stopped me.

    so sad about your impression of Chinese products. But this is what I want to change ...

    And Ray, we do talk about faults here, just you need to talk with right person. I think this is more or less the same all over the world..

    Anyhow, glad to meet all of you here, I hope I get a lot of friends and knowledge here!

    And of course, have fun with you!

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