Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: 445 threshold current?

  1. #1
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,143

    Default 445 threshold current?

    I've got the first of my 445's up and running, doing about 520mW @ 730mA through an Aixiz glass 405 coated lense.

    However I'm having a bit of problem setting my threshold current on my flexmod. At 180mA I get quite a lot of light out still. At the moent I have it at 20mA and its still producing light! Is this right - do all diodes 'leak a bit below threshold, or am i just going to have to ramp it all the way down if i don't want any light spill?

  2. #2
    Join Date
    Nov 2005
    Location
    Melbourne, Australia
    Posts
    3,694

    Default

    Yeah, thats pretty typical of 445nm diodes.. Time to install a shutter...
    KVANT Australian projector sales
    https://www.facebook.com/kvantaus/

    Lasershowparts- Laser Parts at great prices
    https://www.facebook.com/lasershowparts/

  3. #3
    Join Date
    Dec 2006
    Location
    denver,co
    Posts
    1,078

    Default

    I have found these to be pretty leaky at low levels. The big question is how does it look when scanning.

    I would try out some test patterns and adjust your bias to a image and see what looks best. You just don't want some blue eeking out when fully blanked.

    I have been worrying about this too. It will probally come down to a combination of bias setting and color tuning in your software.

    chad


    When the going gets weird, the weird turn pro.


  4. #4
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,143

    Default

    Hmm, no room for a shutter....... looks bloomin great scanned, and i don't do graphics anyway, so probably less critical for colour balance

  5. #5
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,143

    Default

    Hmmm, actually i can get it to go off completely, but it looks like there is a little bit of signal on my FB3 line when it is idle as it comes back on when i plug in the modulation.

  6. #6
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,143

    Default

    One other thing... is it ok to do fine bias adjustments with the diode connected?

    The flexmod instructions say to disconnect and use a meter on the outputs, but what i want to do is just drop it down until the diode goes off.

    Connecting and disconnecting every 10mA increment to see if it has gone off yet is just mind numbing, and probably not so great for the connectors either!

  7. #7
    Join Date
    Dec 2007
    Location
    NorCal / Western Caribbean
    Posts
    710

    Default

    Quote Originally Posted by norty303 View Post
    One other thing... is it ok to do fine bias adjustments with the diode connected?

    The flexmod instructions say to disconnect and use a meter on the outputs, but what i want to do is just drop it down until the diode goes off.

    Connecting and disconnecting every 10mA increment to see if it has gone off yet is just mind numbing, and probably not so great for the connectors either!
    I hooked mine up yesterday and after doing the initial setting setup with a multimeter I decided to tweak it with the diode connected. It didn't seem to have any adverse affect with my diode, however, I may have just been lucky.

    Man these things look good. Waiting on some new scanners to make up a couple of new blue only projectors.

    Can you measure the current whilst the diode is connected or do I have to disconnect it?

    Cheers
    Rich

  8. #8
    Join Date
    Oct 2006
    Location
    Central Florida
    Posts
    7,067

    Lightbulb

    I have not been able to find a way to turn it "on" and nt get any blue light out of it. My Kvant does seem to have the same "issue"... It looks like a built in soft start.
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  9. #9
    Join Date
    Jun 2008
    Location
    Estonia
    Posts
    245

    Default

    Evening,
    I fiddled with my bias settings with the diode connected. Nothing went pop!

    here's some crap video of a few tests I did

    www.445fx.blogspot.com

    Cheers

    Lex

  10. #10
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    1,898

    Default

    set the bias to 100 and that works well. Dr. Lava set mine for me and it works real well.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •