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Thread: DHOM 532nm TEC setup appears to be totally Kaput!

  1. #41
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    Quote Originally Posted by laserkits View Post
    I am also having issues with my 300mw unit from DHOM. It flickers pretty much constantly now. I sent an e-mail to Shawn at Ultralasers over a week ago asking to get the unit swapped under warranty and have not received a reply. This was sent to him within minutes of his incoming mail message where he finally responded to a previous e-mail after a couple of weeks claiming to be out of town... It seems they (ultralasers) are not being very good at after the sale service... FYI for those looking to buy.
    I just purchased a 5W 532, after the bad luck with DHOM I went with VIASHO. Hoping for better times...

  2. #42
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    Update !

    Just received email from Shawn... he is still traveling and won't get back home to Toronto until 10 Aug so his comms are a bit up the spout before then.

    After the Evil ones illuminating posts, I am starting to think that the change from 60cycle 110vsc US mains to 50cycle European 220vac mains might have something to do with these problems.
    Has anyone with 60cycle mains had any problems with instability involving DHOM ???

    @ laserkits
    I have found Shawn to be incredibly helpful up till now so I think your observations concerning "Ultralasers" might be a trifle "hasty" (unlike Shawn's emails LOL).

    However the lack of speed of response if you purchased direct from him is a totally valid criticism which he should deal with PDQ.

    I think that what I personally need more than warranty reassurances, (which all involve shipment back to China) is the relevant technical info about the signals/pin-outs. This would permit me to determine whether the enormous cost/risk/customs hassles etc. involved in shipping back to China are really the best way forward.

    I suspect this is only the case when the "Glued" head module can be determined to be the cause.

    I think DHOM (AND any other Chinese manus) should try very hard to get trusted US and European "service agents" to perform pre-return warranty checks before insisting in "Return to China" as exclusive warranty alternative.
    This may well increase their costs in the short run but would I think solidify their client base fairly quickly.

    Cheers
    Last edited by catalanjo; 07-23-2011 at 07:24. Reason: duh!

  3. #43
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    I have a 300mW DHOM that works great; no modulaiton issues at all and I "think" I am on 60 cycle power mains...

  4. #44
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    Quote Originally Posted by 300EVIL View Post
    I'm not saying this will solve your problem but try warming the head with a hair dryer to about 85F while it's running and monitor output power. KTP does not like to lase when it's too cold. If your power output further degrades, its most likely a TEC fault as you pointed out.
    For the record... tried this but no output increase observed... my 800mw laser looks dimmer than a 5mw laser pen...

  5. #45
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    Quote Originally Posted by laserdj View Post
    For the record... tried this but no output increase observed... my 800mw laser looks dimmer than a 5mw laser pen...
    what about the diode tec not keeping the 808nm cool enough ? may also be a problem if diode drifts away from 808 to much
    When God said “Let there be light” he surely must have meant perfectly coherent light.

  6. #46
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    Update!
    50/60cycle theory shot down completely .......nearly half the people who have PM'd me regarding DHOM instability are running on 60 cycle 110vac.

    Soo..... it is not just in Europe that we are having problems with this make!

    Will try to remain patient but things are not looking so good for DHOM.

    Time for someone to step in with some first hand tech info here!

    At the moment it looks like the higher the power, the dodgier the long term results!

    @badger1666 = looks like there is only ONE TEC here so no "diode" TEC as such... I imagine that the SHG crystal would be the most sensitive to temp changes but if head module is full of glue not much room to maneuver here.
    Also no simple info like "pinouts" of umbilical available as yet, let alone internal details of resonator structure.

    Anyone out there prepared to defend DHOM ?

    Cheers
    Last edited by catalanjo; 07-27-2011 at 17:59.

  7. #47
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    From my tests... I think is a TEC problem but diode related, not xtal.
    I will not open it soon because I got a gig in the next days, but maybe after it I will break my projector apart and take a peek inside the laser head, measure some driver outputs...
    The 800mw green is paired to a quad 445nm module in my projector... in around 15minutes it becomes a 5mw... useless!
    I'm JUST a little mad!!!

    =/

    No response yet from SHAWN@Ultralasers... he could a least come up with the pinout.. would be really helpful.. is it THAT hard?

    Sheesh..

  8. #48
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    Carefull about that B ... Mickael from France says " we were not able to see inside as all was glued..."

    after foam and glue removal just to see what is where and any warranty would be up the spout

    Mind you with an expensive slowboat to China and back on the menu, I am not quite sure how much the "warranty" is really worth anything anyway

    .... a ten day fix after a big transport bill would be a real bummer!

    Cheers

  9. #49
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    For me warranty repair is out of he equation since i cannot ship it out of the country...

  10. #50
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    Take lots of pics when you do the surgery pls..

    I am back in sunny Spain again next week and will be measuring a fully functional 300mw DHOM to get an idea of the signals going down the umbilical.

    PM me if you need any help discerning which bit is what inside the head.

    Have you got measuring equipment...thermometers,oscope,multimeters, etc. ?

    Cheers

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