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Thread: V****o DPSS Green has died, need help...

  1. #11
    Bradfo69's Avatar
    Bradfo69 is offline Pending BST Forum Purchases: $47,127,283.53
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    This is a recurring theme I've seen for a couple years. I steer clear of Viasho at all costs because I've heard SO many people with the same issues. More so than any other laser. (Yeah, I have one of them too and have never gotten it fixed.)

    I understand Stanwax is pretty good with them (and will have him look at mine someday) and might be a cheaper alternative to sending it back to China.

  2. #12
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    My first laser was a viasho still going strong and the tightest beam of all the greens I own.

    My only complain it they take forever and then some to come up to temperature when cold if ambient is in the fifties it can take hours. This was explained to me as the tec is a cool only not a heat cool
    leading in trailing technology

  3. #13
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    The crack almost seems like as if its a result of different in temperature *tec cooling but crystal having like a hot spot somewhere??
    *or just intense heat I guess*

  4. #14
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    Quote Originally Posted by Bbe View Post
    a simple drawing of my laser:

    Attachment 35210
    I can't seem to open this attachment, Bbe. Could you upload it in a .jpg or some other format? Thx.
    The "big green thread" is about building 4-5W lasers (at least it was..I don't know what they're trying for now ) your findings could be interesting. Do you have the unit apart? Could you take some pics of the internals? Thanks!

  5. #15
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    Looking at the pics there does not look like much indium foil about for heat transfer
    Which would help to wards its death
    When God said “Let there be light” he surely must have meant perfectly coherent light.

  6. #16
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    hi guys,

    I had a lot of thought to why it happened. Most likely the crystal was strongly clamped in the holder, therefore it is cracked at the first opportunity. My lasers long time lay in a package , and then i'm was using their in my projector. And the one that died worked no more 20 hours before incident.
    Some guys will say - what do you want from cheap Chinese lasers? A small calculation -4k$/20 hours = $200/hour. Don't expensive? I don't think so.
    When I contacted to Frank with my problem, he replied that there are no problems with the new crystal, but it will not for free. I paid him for his products more than 10k$ and that I want other than a defective device? A rhetorical question
    I really want to see dear Frank in this thread. I really want to see this thread at the top of this forum.
    Could you take some pics of the internals?
    I have tons of photos of the internals of this laser, but I think it contains valuable secrets of Chinese manufacturers If Viasho not take action to resolve our issues, I will publish them.

  7. #17
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    I wouldn't worry about the "revelation" of the internals. Just do it! About the crystals, the photos look as if they are lying on some kind of work surface with the optical surface exposed as well as contacting the underling surface (wood?). If this is true then that's not a good idea. The defect on the KTP will probably be easy to work around, but the vanadate looks odd. This doesn't look like a simple crack, but it is hard to tell. I am also unable to open the attachment.

    The "big green thread" is about building 4-5W lasers (at least it was..I don't know what they're trying for now ) your findings could be interesting. Do you have the unit apart? Could you take some pics of the internals? Thanks!
    Now, more like 10W and kinda complex, so lots of pics of a commercially successful, several W laser would be very useful and maybe a valuable contribution seeing as you have already "cracked the box"

    I can give you an educated guess on the vanadate Nd A% @ 0.6% to 0.8% Is the pump a single free space diode coupled with a lens or is there a fiber involved? Is there is a cavity optic between the pump and the crystal? If so then it is safe to specify AR @ 808nm and 1064 for both surfaces of the crystal. If not then the pump entrance surface will often be HR @ 1064 and act as a cavity optic.

    When I contacted to Frank with my problem, he replied that there are no problems with the new crystal, but it will not for free. I paid him for his products more than 10k$ and that I want other than a defective device? A rhetorical question
    The important question is, "how much"? If not too expensive then don't sweat it, pay it and move on. If a lot, then get angry and decide if you want to try to fix it or send it to him anyway. I doubt you will be able to source a crystal from a third party, keeping in mind the issue of compatibility, for less than the manufacturer can pull from stock.

  8. #18
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    The cavity might be the same as my two 1W heads as mounts look the same and my drivers are shunt-modifiable with IRF460 mosfets

    I'd say the major problem is the coatings quality

    The vanadate is HR1064AR808/AR1064AR808, the KTP is AR/AR, OC is HR1064/AR532, and rear HR is just HR at those wavelengths

    It's a solid design in terms of cavity, but it's a neat thing to replace those screws and there should be a pump correction optic of some sort for the fast axis of the C-mount pump

    Click image for larger version. 

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    BTW Junktronix has some really nice vanadates which would perfectly match the old one and are of great quality!

  9. #19
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    Quote Originally Posted by Bbe View Post
    I really want to see dear Frank in this thread. I really want to see this thread at the top of this forum. I really want to see this thread at the top of this forum.
    You are welcome. I have total 3x3W and 3x4W from Viasho. One of 3W send back for repair, pay close 1k$ and after 20-30hrs I see that problem back again. Without modulation maybe still have power, but at 75% power goes down drastically.
    This 3W head work not bad- nice spot and divergence, so I buy next- this time 4W. Here is... totally defeat
    Work with TEM01 or similar, small part of beam stay at housing window edge, if you want to change something on driver then you must be a patient (the newest, with OLED screen). So my projector have two beam, totaly have about 35mm at 15m distance

    Click image for larger version. 

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    I talk with Frank and send back broken 3W and all my new 4W with bad beam. We still talk via email trough repair time-some delay but all OK. Now you can think how I surprised when I get it. Viasho don't touch this 4W head. They have the same beam like before repair.

    Thanks for time.
    BTW I think that CNI is also not better :P


    Now I have practically question. I can buy in good money 3W Viasho head with broken diode. I think to try replace diode and maybe you know it is possible to change it for

    http://www.ebay.com/itm/808nm-10W-C-...-3xBA#shpCntId
    or
    http://www.ebay.com/itm/Pack-of-10-p...x-iyNUkYaIhf_Q

    (One diode have some lens).
    Last edited by bolo; 09-19-2016 at 03:02.

    1x8W RGB 2x3W G
    3x12W RGB (in progres)
    M2.0 M3.0

  10. #20
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    The 4 W Vashio lasers were originally, and maybe still are, two, 2W lasers combined with a PBS within the head. If you are getting a good output, but there are two separate beams, then the fix is pretty simple. You need to adjust the PBS to get them to realign. You can confirm my assumption by checking that your two beams have orthogonal polarizations.

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